Begin by cutting the chicken breasts into uniform one-inch cubes, ensuring consistent size for even cooking.

Create the marinade by combining one packet of ranch seasoning with 1/4 cup olive oil in a medium bowl.

Add chicken cubes to the marinade mixture, thoroughly coating each piece, then cover and refrigerate for 1-8 hours.

While the chicken marinates, prepare your vegetables: slice mushrooms, cut onion, and bell pepper into similar-sized chunks as the chicken.

Remove marinated chicken from the refrigerator and arrange all ingredients in an assembly line for efficient skewer preparation.

Start each skewer with an onion piece, followed by marinated chicken, then alternate with remaining vegetables, maintaining consistent spacing.

Preheat your Blackstone Griddle on a low setting and apply a thin, even layer of oil across the cooking surface.

Place assembled kabobs on the preheated griddle and immediately cover it with a dome lid.

Cook until the first side develops a golden-brown color, then carefully rotate using tongs.

Continue the rotation process, cooking all four sides until uniformly golden brown, maintaining the low heat setting throughout.

Monitor internal temperature, cooking until chicken reaches 165°F, typically 20-25 minutes total.

Test doneness by checking a middle piece of chicken on the skewer, ensuring proper temperature and golden-brown (not blackened) exterior.