Any tips on how to get my son to eat a little bit more instead of just junk food? He used to like…

Any tips on how to get my son to eat a little bit more instead of just junk food? He used to like eating food, but now he hardly eats anything. All he wants is cookies and chips and juice and I keep trying to give him chicken nuggets, rice, chicken, etc. stuff that he likes. I know they’re gonna want to eat on their own time, but it’s like he doesn’t wanna eat anymore. 😔 It sucks for me too cause then my boyfriends family thinks I don’t feed him at all when that’s not true.