Sriracha bourbon BBQ crockpot chicken: combine the ketchup, bourbon, apple cider vinegar, honey, brown sugar, sriracha, smoked paprika, cumin, garlic powder, onion powder, MSG (if using), salt, and pepper in a medium-sized bowl. This is going to be the liquid in the crockpot.
Remove 2/3rds of a cup of the liquid to be turned into extra BBQ sauce. Place this 2/3rds cup aside to work with after you have the crockpot cooking.
Add 2 pounds of chicken to a crockpot and then pour in the BBQ sauce base and toss the chicken in the sauce to coat everything. Turn the crockpot on high and cook for 3 to 4 hours.
Sriracha bourbon BBQ sauce: add the 2/3rd cup reserved sauce to a small pot over medium heat and bring to a simmer.
Simmer for 10 to 15 minutes. At this point, the sauce should be thickened and sticky.
Remove the pan from the heat and store the barbecue sauce in a sealed container in the refrigerator.
After 3 or 4 hours remove each piece of chicken to a cutting board. Using two forks, pull the chicken into smaller pieces put it back in the crockpot, and mix with whatever sauce is remaining.
Store any leftover pulled BBQ chicken in the fridge for up to 5 or 6 days
Marinated slaw: slice scallions and add them to a bowl with the rest of the cole slaw mix. If you can't find cole slaw mix, you can use 1/2 green cabbage shredded and 1 carrot shredded and add that in with the scallions.
Add the rest of the slaw ingredients to a second bowl and whisk to combine. Once combined pour over the slaw mix and scallions and toss to coat everything.
Keep the slaw in a sealed container in the refrigerator for up to a week.
Sandwich assembly: toast your sandwich buns.
Top the bottom bun with a generous portion of sriracha bourbon BBQ chicken and then drizzle more BBQ sauce on top if desired.
Top the chicken with slaw and then close the sandwich with the top bun.