If pork roast comes in netting or is tied, remove netting or strings. In 3- to 4-quart slow cooker, place pork. Pour beans around pork. Sprinkle dry taco seasoning mix over pork. Pour green chiles over beans.
Cover and cook on Low heat setting 8 to 10 hours.
About 45 minutes before serving, in 3-quart saucepan, make rice mixes as directed on package, using water and butter.
Remove pork from cooker; place on cutting board. Use 2 forks to pull pork into shreds. Return pork to cooker; gently stir to mix with beans.
To serve, spoon about 1 cup rice into each serving bowl, top with 1/2 cup pork mixture, 1/4 cup cheese, 1/4 cup lettuce and about 1 tablespoon salsa.