Add chicken breasts, jalapeño, 2 cups Hatch Green Chile Salsa, chicken stock, cayenne pepper and salt to a slow cooker. Cook on high for 3 to 4 hours.
Remove chicken from the slow cooker to a large bowl. Using two forks, shred chicken. Stir in remaining Hatch Green Chile Salsa.
To assemble the sliders, add the bottom halves of the slider buns to a sheet pan. Top with 1/3 cup of the green chile chicken and a slice of pepper jack cheese.
Place sheet pan under broiler set to high until cheese is melted, approximately 1 to 2 minutes.
Top sliders with fried onions, sliced jalapeños and more Hatch Green Chile Salsa as desired. Finish with the top halves of the slider buns.
Serve immediately.