Prepare a large pot of water and bring it to a rolling boil. Cook the fresh ramen or udon noodles according to package instructions, usually around 3-5 minutes, until they're just tender but still chewy. Drain and rinse under cold water.

In a small bowl, whisk together 2-4 tablespoons of gochujang, soy sauce, brown sugar, sesame oil, and minced garlic until smooth. If thick, add a splash of water.

Heat a tablespoon of oil in a large skillet. Add in your boneless chicken thighs and cook for 6-8 minutes until golden brown and cooked through (165°F). Flip occasionally.

Pour the gochujang sauce over the chicken in the skillet. Stir to coat and let it simmer for 2-3 minutes until glossy.

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

Serve the Korean Spicy Chicken Noodles in bowls, garnishing with freshly chopped scallions and sesame seeds. Enjoy while hot!