Place chicken in slow cooker with salsa, lime juice, garlic, and black beans. Cook on low for 7-8 hours or high for 5-6 hours. Shred chicken. Season with mexican seasoning.
Spread tortilla chips on a baking sheet. Layer on white cheddar and chicken. Broil in oven for 3-4 minutes. Top with red onion, green onion, serrano pepper, and cilantro.
Recipe by Rachel Schultz at https://rachelschultz.com/2018/04/17/slow-cooker-chicken-nachos/