OMG is my 20 month old a picky eater anyone else with the same problem and/or had the same problem? how did you resolve it?

My son ONLY want to eat cheese, soups, and not just any chicken nuggets but the chicken nuggets from McDonald's... Oh also Peanut Butter sandwich, breads and Mac & Cheese... THATS IT!!

He has been eating this for the past 5-6 months, also i have been giving him Enfagrow just to make sure he is not missing any iron vitamins etc.