Place 1½ cups of salsa in the bottom of the slow cooker, along with corn and beans. Coat chicken all over with taco seasoning and nestle in the salsa mixture.
Top with remaining ½ cup salsa and butter cubes.
Cover and cook on high for 2 hours or low for 6 hours.
Transfer chicken to a cutting board, shred with two forks, then stir back into the salsa mixture. Serve over rice with your choice of toppings.
Instant Pot directions:
Follow directions through Step 2, but place everything in the inner pot of the pressure cooker. Secure the lid and close the pressure valve. Cook on manual for 10 minutes at high pressure. After the timer goes off, use a quick release to release the pressure. Remove the lid. Continue with recipe in Step 4.