In a medium bowl, whisk together the ketchup, honey, molasses, apple cider vinegar, chili powder, smoked paprika, garlic powder, kosher salt, and black pepper until smooth. This is your homemade BBQ sauce.

Place the chicken breasts in the bottom of a slow cooker. Pour the BBQ sauce evenly over the chicken. Cover and cook on low heat for 3 to 3 1/2 hours, or on high for 2 hours, until the chicken is tender and cooked through.

Carefully transfer the cooked chicken to a large bowl, leaving the sauce behind in the slow cooker. Whisk the cornstarch into the sauce until completely dissolved. Turn the slow cooker to high and cook uncovered for 10 minutes, stirring occasionally, until the sauce thickens.

While the sauce thickens, shred the chicken using two forks. Add 3/4 cup of the thickened sauce, the softened cream cheese, shredded Monterey Jack, and chopped cilantro to the shredded chicken. Stir until everything is well combined and creamy. Reserve the remaining BBQ sauce for serving.

Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper.

To make rolling easier, warm the tortillas in the microwave between damp paper towels for about 30 seconds, just until pliable. Working one at a time, spoon about 1/4 cup of the chicken mixture onto the lower third of a tortilla. Roll it up tightly, tucking in the sides as you go.

Place the taquitos seam-side down on the prepared baking sheet. Repeat with the remaining tortillas and filling. At this point, you can freeze some or all of the unbaked taquitos for later (see notes).

Lightly spray the taquitos with cooking spray and sprinkle with a pinch of flaky sea salt. Bake for 12 to 16 minutes, until the taquitos are lightly golden and crisp. Serve warm with the reserved BBQ sauce for dipping.