2 months?

Sure! Just to be clear, this is lifetime sales, right?

I choose 1.5-2 Millions, hope it's as good as it looks and it will sell better than that

The game seems pretty fleshed out for a Mario sports game and Switch first-party games are generally selling more than their predecessors, so I think it can pass 2 million.

The ability for the Switch to have local mutliplayer anywhere makes a game like Mario Tennis Aces way more enticing than it would be on a standard console. Add in motion controls to grab a bit of the Wii Sports crowd and I think Aces will end up being the best selling Mario Tennis game as long as Camelot makes a good game.

Yup! I'm genuinely not convinced at all of this title's potential when compared to historical sales for Mario Tennis.

Two and a quarter mil I'll wager. There's a bunch of factors in it's favor this time around:
* No Wii Sports to overshadow it with a tennis title literally everyone owns.
* Motion controls are back
* Story mode is back
* Contents looks like game will have more than any of the other recent titles
* Gameplay seems to be refined, offering a balanced system, while offering the vanilla mode as well
* Advertising seems to be significantly improved over other recent entries. (Anecdotally, this is the first one I've heard about before release, and I've been around since it started.)
* Lack of titles to compete for the casual crowd.
* On a system that's designed for multiplayer (As opposed to GBC,GBA,3DS)

I really miss that series, Top Spin 2 was the primary reason I bought an X360 to play online matches. Fun days

About 1 million physical copies.

1.5 million