Slice the chicken breasts into thin strips about a quarter-inch thick.

Pour 6 cups of water into a large pot and bring it to a rolling boil over high heat.

Add 2 tablespoons of butter to a medium skillet over medium-high heat.

Add the sliced chicken strips and cook for 5 to 6 minutes, stirring occasionally, until they're golden brown and cooked through.

While the chicken cooks, whisk together the gochujang, soy sauce, rice vinegar, sugar, minced garlic, and sesame oil in a small bowl until smooth.

Once the chicken is cooked, pour the sauce mixture over it and stir constantly for 1 to 2 minutes.

Add the ramen noodles to the boiling water and cook for 2 to 3 minutes, breaking them up halfway through.

Drain the noodles in a colander, saving about a cup of the cooking water.

Add the drained noodles directly to the skillet with the chicken and sauce, tossing everything together for 1 to 2 minutes over medium heat.

Taste and adjust seasoning with salt, pepper, or additional gochugaru if desired.

Plate and add sliced green onions and sesame seeds on top before serving.