Heat your oven to 375°F and prepare a baking sheet with parchment or a light coating of oil.
Combine all the honey mustard sauce ingredients in a big bowl and stir until smooth.
Reserve half of this sauce for later use.
To the remaining sauce in the bowl, whisk in the egg thoroughly.
Cut the chicken into bite-sized pieces and stir them into the egg and sauce mixture until well coated.
Allow the chicken to sit a few minutes to absorb the flavors.
In another bowl, mix together tapioca starch, garlic powder, salt, pepper, and crushed pretzels.
Toss the marinated chicken pieces in the pretzel coating until covered evenly.
Arrange the coated chicken pieces on the baking sheet in a single layer.
Spritz the chicken lightly with avocado oil spray.
Cook in the oven for 25 to 30 minutes, turning them over halfway through baking.
While the chicken cooks, prepare quick pickled cucumbers by mixing sliced cucumbers, apple cider vinegar, and salt in a bowl; set aside.
Lightly cook the corn in a skillet for a couple of minutes until heated.
Warm the cooked rice, then distribute it evenly into four serving bowls.
Top each bowl with the crispy pretzel chicken, sautéed corn, pickled cucumbers, halved cherry tomatoes, and optional avocado slices.
Drizzle the reserved honey mustard sauce over each bowl and serve warm.