Does anyone have any tips on getting my daughter to get over her picky eating ?

So she doesn't gain weight that much she's not loosing which is a good sign but she doesn't gain weight she's 5 and only weighs 31lbs her 4 year old sister weighs 32 well we took her to the dr and they did a blood test which didn't show nothing abnormal it just showed she's low on iron and vitamin D so she's on supplements now

But the thing is she does have appetite she gets hungry but just for things like chicken nuggets like "kid friendly" things she does eat rice and stuff but she now hates pasta like spaghetti she used to love it now she doesn't she loves to eat fruit and vegetables but not like what I consider real food she doesnt like a lot of stuff I get worried

I am also a naturally thin person I've never really gained that much either even while pregnant I've gained very little so dr said she could be the same as me by genetics but the thing is she's a picky eater and I feel like no matter what I tell her she doesn't get over it

The dr said it could well be that she's naturally thin cause I'm 23 and barely weigh 90lbs but first I want to see if she gets over her picky eating if she still doesn't gain much then shes probably just like that