In a large skillet heat 2 Tbsp olive oil with 1 clove of garlic for 1 minute. Add the spinach, a bit at the time.
In a few minutes the spinach will drastically reduce their volume. Season with 1/2 tsp sea salt, mix and turn the heat off.
Remove the garlic. Let the spinach cool down completely before squeezing out all the extra liquid. Place them on a cutting board and chop them finely. Set them aside.
Prepare one bowl with 1 1/2 cup breadcrumbs and one with 2 beaten eggs.
In a large bowl add the ground chicken, the cooked spinach, one egg, 1/2 cup breadcrumbs, 1/2 tsp sea salt, 1/2 tsp nutmeg. Mix together.
Wet your hands with water. Scoop one tablespoon of chicken mix in your hands and create a round croquette. Coat the croquette with the egg wash, then coat it with breadcrumbs, coat again in the egg wash and finish with a last coat of breadcrumbs. Keep preparing the other croquettes using all the mix.
Heat 2 Tbsp of olive oil in a skillet for 1 minute at low heat. Add 4 croquettes when the oil is nicely hot and let them cook for around 4 minutes. Flip on the other side and cook for other 4 minutes. Cook the croquettes in batches, for every batch add 2 Tbsp olive oil at the beginning.