As a toddler also struggles to assert his independence from his parents, he often wages battles over eating, sleeping, and toileting. While it is understandably frustrating, it is an important part of his development. Your son may be even more defiant in response to your recent move. He had no control over relocating, but he can exert enormous control over what goes into his mouth!
So what can you do? First, try to relax. Children are quite good at getting enough quality calories. Each meal may not be perfectly balanced, but over the course of a week, he'll do fine. Continue healthy, regularly scheduled meals and let your toddler choose what and how much he will eat. Offer nutritious snacks like milk, cheese, fruit, whole grain breads or crackers. Limit juice to one glass per day. The fact that he doesn't eat sweets is good. Candy, soda, and other sweets can ruin appetites and promote cavities. Do not use food as punishment or bribery and never force your child to eat.
Many parents share your worry about "picky eaters" not getting enough to eat or eating the right foods. It sounds like your son is eating some and at least he's not losing weight. If you are still concerned, a visit to his doctor may reveal that he has grown more than you thought and a physical exam can reassure you that there are no real medical concerns.