Preheat your oven to 400°F. This is an essential step to ensure your meatballs cook evenly and develop a nice golden color.
Prepare a 9×13-inch baking pan by spraying it with nonstick spray. This will prevent the meatballs from sticking and make cleanup a breeze.
In a large mixing bowl, combine the ground chicken, breadcrumbs, diced onion, minced garlic, salt, pepper, and egg. Mix everything thoroughly until well combined. You want the mixture to be cohesive but not overworked.
Next, it's time to shape the meatballs. Using a cookie scoop or your hands, portion the mixture into 24 equal-sized meatballs. Each meatball should be about the size of a US quarter – not too big and not too small!
Once you’ve shaped all the meatballs, place them in the prepared baking pan, leaving a little space between each one for even cooking.
Place the baking pan in the oven and bake the meatballs for about 20 minutes, or until they turn a lovely golden brown.
After 20 minutes, take the meatballs out of the oven and pour the red enchilada sauce over them, ensuring they are well covered. Then sprinkle the shredded Monterey Jack cheese on top.
Return the pan to the oven for an additional 5 minutes, or until the cheese is melted and bubbling.
Finally, remove the meatballs from the oven and garnish with chopped fresh cilantro if desired. Serve them hot and watch everyone enjoy!
