Add chicken to slow cooker. Spread butter tabs evenly. Combine ranch powder, cumin, chili powder, onion, powder, and garlic powder. Sprinkle evenly over chicken. Secure lid and cook on high for 4 hours (or low for 8 hours).
Remove chicken from slow cooker, and chop. Then return to slow cooker and stir with any juices.
Start with a tortilla and add lettuce, onion and sprinkle of cheese. Next add chicken, drizzle of ranch dressing and sprinkle of crushed chips.