Set your Instant Pot to the saute setting. Heat the canola oil; add the onion, ginger and garlic. Cook, stirring frequently, until browned, about 4-5 minutes.
Stir in the cilantro, whole cloves, star anise pods, cinnamon, fennel seeds, coriander and peppercorns. Press cancel to turn the saute option off.
Add the chicken thighs, chicken stock, fish sauce, brown sugar, 1/2 teaspoon of salt and 2 cups of water into the pot. Select the manual setting and cook on high pressure for 18 minutes. When finished cooking, do a quick-release to release the pressure according to the manufacturer’s directions.
Open the pressure cooker and transfer the chicken to a plate. You can slice the chicken or using two forks, shred the chicken and discard the bones. Set the shredded chicken aside.
Strain the broth through a fine-mesh sieve lined with cheesecloth; discard the solids. Skim any remaining fat from the surface and discard; season with salt and pepper to taste. You can also season with additional fish sauce, if desired. Return the broth to the instant pot and keep warm.
In a large pot of boiling water, cook the noodles according to package instructions; drain well.
To serve, divide the noodles and shredded chicken into serving bowls. Pour the hot broth over and serve immediately, garnished with bean sprouts, fresh herbs, scallions, chili peppers and lime wedges.