Step 1) Cut pork into 1 inch cubes; season with salt and pepper. Heat oil in large skillet or Dutch oven. Add pork, onions, garlic powder, chili powder and chipotle chile; Sauté 3 to 5 minutes to brown the meat.
Step 2) Add enough water to almost cover pork. Bring to a boil; cover, reduce heat and simmer 30 minutes. Remove lid and continue to simmer an additional 45 minutes or until liquid has evaporated.
Step 3) Combine chopped tomatillos, tomatoes and cilantro in a small bowl.
Step 4) Place an equal amount of pork on each tortilla. Top with tomatillo salsa.