Too many unknown factors at this point. But people saying no less than 100 million are forgetting just how bad a console company’s fortunes can change generation over generation.

If Nintendo releases the Switch with minimal upgrades, it likely won’t fall completely flat, but it’s going to sell fewer units than Switch 1. If it comes with a new feature that backs a killer app, then the potential grows considerably - this happened with touchscreens and motion controls in the Wii and DS generation. But Nintendo has been known to make stupid moves in the past:
N64: cartridges - that hamstringed the console against the PSX which could get much larger games on the console for a much cheaper price to the developer/publisher and consumer. This was a massive stumble because Nintendo was synonymous with video games in the later 16-bit generation. Neither Sony nor Sega had a particularly stellar launch of their 32-bit consoles. PSX took off because Nintendo fumbled the N64. And PSX’s dual shock stole the thunder of arguably the N64’s best feature (analog sticks).
Gamecube: PS2 except missing vital features - mostly the console was an imitation of the PS2, except with a less usable controller, smaller media, missing DVD playback, and less aesthetically pleasing.
Wii U and 3DS both suffered a similar problem: the new features didn’t make games simpler, didn’t yield many ideas from Nintendo themselves. Both consoles felt outdated at the time of release, and without a killer app (like a Super Mario Bros, Wii Sports, or Mario Kart 8 Deluxe/Breath of the Wild). On 3DS’s side, the 3D feature was hit heavily by anti-3D marketing from tabloids - I don’t think it’s unfair to say that outside and uncontrollable circumstance damaged the handheld’s potential. I don’t think it’s likely Switch 2 will have a feature that terrifies the tabloid spinners. But the amount of seizures the 3DS caused is likely less than Pokémon.

Where Nintendo does well is when it packages greater complexity into more simplistic interfaces and features. The NES did this with two action buttons and a D-Pad, the SNES took on arcade complexity and perhaps improved on the design by adding the diamond face buttons and shoulder buttons. The N64’s analog stick for 3D was a great idea too for simplifying and improving 3D movement (but cancelled out by the cartridge thing). The Wii and DS added motion (IR, accelerometer, and later gyro) and touch controls which simplified gaming further and added some complexity at the same time, and all in a very entertaining way. The whole Switch concept greatly increased the convenience of handheld/home console gamers like myself while at the same time being sufficient for those who handheld games only or home console gamed only.

What comes next? That’s the multi-billion dollar question. Almost everyone has opinions on that. There are a lot of different possibilities.

The other thing is the fact that Nintendo often underestimates the potential of their own ideas, and other companies end up picking them up and running with them much further than Nintendo: casual games, touch screens, and fitness applications. And it’s not a situation where Nintendo tried and failed, Nintendo tried and succeeded with these concepts, but then abandoned them or scaled them back. So, we can’t underestimate Nintendo’s potential to abandon the golden goose before her chicks hatch.

There are too many factors to consider right now. Perhaps after some revelation about the console.

Too many unknown factors at this point. But people saying no less than 100 million are forgetting just how bad a console company’s fortunes can change generation over generation.

If Nintendo releases the Switch with minimal upgrades, it likely won’t fall completely flat, but it’s going to sell fewer units than Switch 1. If it comes with a new feature that backs a killer app, then the potential grows considerably - this happened with touchscreens and motion controls in the Wii and DS generation. But Nintendo has been known to make stupid moves in the past:
N64: cartridges - that hamstringed the console against the PSX which could get much larger games on the console for a much cheaper price to the developer/publisher and consumer. This was a massive stumble because Nintendo was synonymous with video games in the later 16-bit generation. Neither Sony nor Sega had a particularly stellar launch of their 32-bit consoles. PSX took off because Nintendo fumbled the N64. And PSX’s dual shock stole the thunder of arguably the N64’s best feature (analog sticks).
Gamecube: PS2 except missing vital features - mostly the console was an imitation of the PS2, except with a less usable controller, smaller media, missing DVD playback, and less aesthetically pleasing.
Wii U and 3DS both suffered a similar problem: the new features didn’t make games simpler, didn’t yield many ideas from Nintendo themselves. Both consoles felt outdated at the time of release, and without a killer app (like a Super Mario Bros, Wii Sports, or Mario Kart 8 Deluxe/Breath of the Wild). On 3DS’s side, the 3D feature was hit heavily by anti-3D marketing from tabloids - I don’t think it’s unfair to say that outside and uncontrollable circumstance damaged the handheld’s potential. I don’t think it’s likely Switch 2 will have a feature that terrifies the tabloid spinners. But the amount of seizures the 3DS caused is likely less than Pokémon.

Where Nintendo does well is when it packages greater complexity into more simplistic interfaces and features. The NES did this with two action buttons and a D-Pad, the SNES took on arcade complexity and perhaps improved on the design by adding the diamond face buttons and shoulder buttons. The N64’s analog stick for 3D was a great idea too for simplifying and improving 3D movement (but cancelled out by the cartridge thing). The Wii and DS added motion (IR, accelerometer, and later gyro) and touch controls which simplified gaming further and added some complexity at the same time, and all in a very entertaining way. The whole Switch concept greatly increased the convenience of handheld/home console gamers like myself while at the same time being sufficient for those who handheld games only or home console gamed only.

What comes next? That’s the multi-billion dollar question. Almost everyone has opinions on that. There are a lot of different possibilities.

The other thing is the fact that Nintendo often underestimates the potential of their own ideas, and other companies end up picking them up and running with them much further than Nintendo: casual games, touch screens, and fitness applications. And it’s not a situation where Nintendo tried and failed, Nintendo tried and succeeded with these concepts, but then abandoned them or scaled them back. So, we can’t underestimate Nintendo’s potential to abandon the golden goose before her chicks hatch.

There are too many factors to consider right now. Perhaps after some revelation about the console.