If GoW can push PS4 this much after 4 years on the market, Pokémon will push the Switch significantly. I don't think we can question Nintendo's estimate.
On another note, I don't get why people defend the sales of a console by the lack of games. Games is what make a system and lack of games is a weakness of a console and not an excuse. Switch is selling Ok but for the last few months people feel the need to defend the Switch by claiming the lack of games.