Add 2 tablespoons vegetable oil to a large saute pan and place over medium-high heat. Add chopped pork and season with salt and pepper. Cook and stir until lightly browned. Add dry, minced onion and cook and stir for another minute or two. Transfer pork to Crock-Pot.
Add remaining vegetable oil to the same saute pan and place over medium heat. Add onions, celery, garlic, and jalapeno. Cook and stir for two to three minutes, until vegetables have softened a bit. Transfer vegetables to Crock-Pot with the browned pork.
Add green salsa, green enchilada sauce, diced tomatoes, and chicken broth to Crock-Pot and stir to combine. Place lid on the slow cooker and cook on HIGH for one hour. Turn to LOW and cook for an additional 5 to 6 hours or until pork is fork tender.
Serve over rice with slices of avocado and sour cream garnish.
Combine any leftover rice with chile verde. Freezes well.