My toddler doesn't eat much?

I wish I could get my toddler to eat more. She has a very small choice of foods which include include: Gerber's Sweet Potatoes, El Pollo Loco Chicken, toast with cinnamon, Gerber's squash, Gerber's Carrots and Mac & Cheese. She drinks apple juice, 2% Milk and water. That's it....My main concern is her not getting enough nutrients. She gets toddler vitamins, but who knows if that stuff really works. Any suggestions? We have tried offering her other foods but she turns her nose at it.