Cook the fresh ramen or udon noodles according to the package instructions, usually around 3-5 minutes until just tender. Drain and rinse under cold water to stop cooking. Set aside.

In a mixing bowl, whisk together gochujang, soy sauce, brown sugar, sesame oil, and minced garlic until smooth. Add a splash of water if needed to thin the sauce.

Heat a tablespoon of oil in a large skillet over medium-high heat. Add the boneless chicken thighs, cooking for about 6-8 minutes until golden brown and cooked through. Stir occasionally.

Pour the gochujang sauce over the cooked chicken in the skillet. Stir to coat evenly and cook for an additional 2-3 minutes until glossy.

Add the cooked noodles to the skillet, tossing everything together for 1-2 minutes until heated through and well coated.

Serve the noodles in bowls, garnishing with scallions and sesame seeds. Enjoy hot.