Cut the chicken into small pieces about 1/8 inch in size.
In a medium bowl, whisk together the eggs and buttermilk until combined.
In a large bowl, whisk the flour, salt, pepper, paprika, and garlic powder until evenly mixed.
Pour the egg mixture into the dry ingredients and stir until a batter forms.
Add the chopped chicken, shredded mozzarella, shredded cheddar, and sliced green onions to the batter and mix until everything is evenly distributed.
Heat about 1 inch of vegetable oil in a large skillet over medium-high heat until shimmering and hot.
Scoop about 1/4 cup of the batter per fritter and carefully drop into the hot oil, spacing them so they don’t touch.
Fry each fritter 4–5 minutes per side, turning once, until golden brown and the chicken is cooked through.
Remove fritters to a paper towel–lined plate to drain briefly before serving.