In a medium skillet, bring the chicken stock and non-alcoholic malt beverage to a gentle simmer.
Add the chicken breasts and poach for about 10 minutes, turning once halfway through.
While the chicken cooks, heat olive oil in another skillet over medium-low heat.
Add garlic and onion, sauté until soft and fragrant.
In a bowl, combine Worcestershire sauce, hot sauce, grill seasoning, brown sugar, and tomato paste.
Add two ladles of the poaching liquid to the mixture and stir well.
Remove the chicken, slice, then shred using two forks.
Mix the shredded chicken into the sauce mixture thoroughly.
Transfer everything into the skillet with onions and garlic.
Simmer for 5–10 minutes until the BBQ Chicken Sandwiches filling becomes rich and saucy.
Mix chopped sour and sweet pickles in a small bowl.
Fill buns with shredded chicken and top with pickle relish. Serve warm.