Offer only healthy meals, the same meals you make for the rest of the family. Nuggets and biscuits aren't okay for a 2 year old. If he doesn't eat from the healthy selection, have him sit at the table for a sufficient and polite period of time and then excuse him. He will eat when he is hungry. Don't give him treats like chocolate unelss he eats his main meal, but don't bribe him either.
Make sure you aren't letting him fill up on milk or other liquids. Offer him just a a few ounces of water with his meal. Try to giv ehim run around and exercise right before a meal. And if there is one meal he is more likely to eat at, like breakfast, load in the protein and vitamins there. My 2 year old doesn't eat more than a few bites of dinner, that's just her. So I lead up the veggies at lunch.
Not all kids are big eaters and even those that are slow down around 3. You will notice more periods of average eating interspursed by "growth spurts" lasting weeks where he iwill probably eat a ton.
Right now this sounds behavioral. He has trained you to only give him the junkier foods he really likes and he doesn't have any consequence for not eating. If you are concerned there is a health problem, take him to the pediatrician and have his weight checked.