Are there any good healthy foods or dishes I can prepare for a 10yo who only likes junk food?

Yes! First, rapist that you are the parent. Then, realize that your child does not have the income to buy food on a regular basis. You control the food in the house, so make the food you want the kids to eat and stop buying the stuff you don't want them to eat. Unless the kids can get a job and buy all their own food, they will be eating whatyou ned them to eat today!
Habits must change! If your 10yo only eats junk food, that is a long standing habit that he's been allowed to develop. You're in for a tough time changing it. Start slowly with foods that are not too objectionable to him. Give him a little white meat chicken instead of nuggets, a baked potato instead of fries. Introduce veggies later. Above all, be prepared to let him be a bit hungry and unhappy. He won't starve.