Heat a large Dutch oven over medium-high heat. Add a drizzle of sesame oil, then add the garlic, shallots, ginger, and red pepper flakes. Cook, stirring occasionally, until caramelized, about 3 minutes. Pour in the chicken broth, coconut milk, and soy sauce, then whisk in the chili paste. Reduce the heat to medium-low and simmer for 10 minutes.
Meanwhile, make the chicken. Set up a dredging station (one bowl of beaten egg, one bowl of panko breadcrumbs). Season chicken with salt and pepper. Dredge both sides of the chicken through the eggs, then the panko, pressing to adhere by using your hand to really pound the crumbs in. Air-fry the chicken at 375F for 8 minutes per side, or bake in an oven at 400 for 10 minutes per side. Watch closely to remove the chicken when it is fully cooked through and the breadcrumbs are golden brown. Set aside. Once cooled, slice the chicken into thin strips.
To the soup, stir in the noodles, spinach, and sesame oil. Let sit for 5 minutes or until the noodles are soft
To serve, divide the noodles between bowls and ladle over the soup back overtop. Add the chicken. Top as desired with eggs, green onions, sesame seeds, and red chiles. Serve immediately.