Pre boil broccoli and Potato and allow to cool. Broccoli takes around 20 minutes and the potatoes 20-30 minutes depending on how much you use.
While potato and broccoli is cooking empty bread crumbs and egg whites in to seperate large bowls. (if you prefer you can use a ziploc/resealable bag for the breadcrumbs).
Once potato and broccoli has boiled, empty water and add broccoli to potatoes. Mash as best as possible and add a little milk and butter. (NEVER add salt to a young childs food)Dont make too runny as you will need to mold it!
Roll potato/broccoli into a ball a little smaller then a golf ball. Roll in the breadcrumbs ans then place on a plate.
Cut the chicken into portions you think will be suitable for your child. Dip in the egg white (make sure the whole nugget gets covered) Then place in breadcrumbs and shake until chicken covered.
Place in the oven at 200C/400F and cook for 20-35 minutes. Check the chicken has cooked through by breaking a nugget open. Allow to cool and then serve!