Preheat oven for the waffle fries according to package directions. Arrange them on a baking sheet and place in the oven. Cook until nice and golden brown on both sides.
While the fries are cooking, heat a large, nonstick skillet over medium-high heat. Add EVOO and ground chicken. Using the back of a wooden spoon or spatula, break the meat up into bite-size pieces so it browns evenly. When the meat has browned, add onion and pepper.
While the chicken and veggies are cooking, make the BBQ sauce: In a bowl, combine brown sugar, vinegar, grill seasoning, Worcestershire sauce, tomato sauce and hot sauce. Stir to combine.
When the vegetables become tender, add the BBQ sauce to the skillet, reduce heat to medium and cook for 5 minutes. Reduce heat and simmer an additional 5 minutes.
While the Sloppy Joe filling is simmering, melt the butter in a medium-size saucepot. Add flour, cook 1-2 minutes over moderate heat, then whisk in the chicken stock and mustard. When the stock comes to a bubble and starts to thicken, stir in the cheese with a wooden spoon. Remove from the heat and reserve for fries.
Using a large spoon or ice cream scoop, pile the filling onto the toasted and buttered bun bottoms, and top with pickles. Cover the Sloppy Joes with the bun tops and serve with a handful of waffle fries topped with lots of cheese sauce alongside.