Is there a way to unlock the missions in COD MW 3 on Wii without completing previous levels?

The first thing you need to do to get the Nuke is to get to Rank 20 in the game. Before you are Rank 20 you do not have the ability to unlock the Nuke in COD Mobile. Once you get to Rank 20 it is an item that will unlock for you and it doesn't need to be equipped or anything like that

Thank you for your assistance. But I have already found a great resource to buy CoD MW leveling and should say it works pretty well for me. You see, the game appeared to hard to go through because I`m quite lack of time. So, I simply turned to those experts to level up and get some more cool weapon.