Virtually every release of a Nintendo IP on Switch becomes the fastest-selling or even best-selling installment in a series. I'll say 4 million plus, putting Origami King as the best-selling Paper Mario game.
If Nintendo built up more hype and it was a classic-style Paper Mario game, I would say 6 million plus.

Well, to me Animal Crossing looks like about the most boring game ever made, yet it's selling like crack.

Our feelings as enthusiast gamers aren't always reflected in real world sales.

I think it'll vastly outsell the previous best selling paper mario, like pretty much every Ninty franchise is doing on the Switch. I wouldn't be surprised for a 1.5+ mil launch weekend, 4 million by end of year, and like 8 million lifetime.

I 100% agree. I don’t even plan to ever touch AC,  but I do see its mass market appeal and historical data has shown that too, whereas PM has never been a big seller.  

Anyway, I am really disappointed with Nintendo’s first party output this year. Very underwhelming year so far. 

I would guess between 3 and 4 million. Sticker Star did about 2.5, and with the momentum of the Switch, and not much releasing atm, it should be able to surpass that.

Yeah, I too have found Nintendo's output this year extremely poor.

The last first party game I bought was Luigi's Mansion 3 last October and it's looking like I might close out this entire year with only third party purchases. Some years of the Wii U were better than this.

Around 4.5M would be my guess. Potentially more if the US go into lockdown again soon.

2m if that. It doesn't look exciting at all, I just don't understand who its target market is supposed to be.

Around the Wii game. 4M.

Paper Mario is not as big as Licences like Animal Crossing , or big Mario games