Loaded Cheesy Grits

1 lb. spicy bulk pork sausage1 small onion, chopped4 c. water½ t. salt1 c. quick-cooking grits3 (4-oz.) can chopped green chilies1 ½ c. shredded sharp cheese, divided1 ½ c. shredded Monterey Jack cheese, divided2 T. butterTabasco to taste2 large eggs,…