MH4JP + MH4U ROTW(Minus Japanese version) sold over 5 million units.The payment was for the exclusivity. They were negotiating different exclusivity options, including one where they wouldn't release the game on PC. The thing all the options had in common was console exclusivity for Switch.
But mixing that document with the other one with the Capcom titles line-up roadmap for the next 4-5 years, seems that the option they agreed is to release Rise on PC 9 months after the Switch release, and to announce the PC version 6 months after the Switch release.
But who knows, since all this stuff has been leaked and now many people knows it will be released on PC maybe it affects to the Capcom deal with Nintendo and they update it because it may hurt the sales of the Switch version since people may skip the Switch version to play the superior PC version. Another leaked document even listed the improvements of the PC version like increasing the FPS from 30 to 60, and so on, detailing to the point it mentioned optimized controls for keyboard and mouse and adapted UI.
Adding the PC numbers I think they can achieve it, but in Switch alone I think it will be difficult. How many non-Nintendo games sold 10M+ units on Switch alone?
With Nintendo Switch popularity and MH franchise exposure on the eest after MHWorld it could potentially reach 10M units.
Japan - 5 million units LTD
US - 2 million units LTD
EU and ROTW - 3 million units LTD