Start by washing the zucchini and grating it finely. Chop your onion and set both aside.
In a large mixing bowl, combine the ground chicken, chopped onion, shredded zucchini, seasoned bread crumbs, egg, salt, and black pepper. Use your hands to mix everything until well combined.
Take a small amount of the mixture and shape it into a small patty or oval, about 2-3 inches long. Repeat until all the mixture is used.
In a frying pan, heat 2 tablespoons of olive or vegetable oil over medium heat.
Once the oil is hot, carefully place the croquettes in the pan, making sure not to overcrowd them. Cook for about 4-5 minutes on each side or until they are golden brown and cooked through.
Once cooked, place the croquettes on a paper towel to drain excess oil. Serve warm with a dollop of sour cream and a sprinkle of fresh dill on top.