I would describe the N64 as having been a "middling success" and the Switch will likely outsell the N64 in its first two years on the market.
With regards to last-gen, the 3DS did sell well but don't forget that Nintendo had to make huge price-cuts to kick start it and Nintendo also made almost no money on Wii U sales due to the outdated custom-tech in the gamepad. The Switch is a legitimate success because it had a strong launch and is sustaining strong sales a price-point that Nintendo can make money on.
I would describe the Switch as a definite and strong success. Maybe not as insane as the Wii was but I think that the Switch may have longer legs and stamina than the Wii.