I'm now doing all 3 tiers at the moment.

Toast walnuts on rimmed baking sheet, occasionally tossing, until fragrant and slightly Darkened

Pulse 3/4 Cup walnuts in a food processor or blender till finely chopped (keep remaining walnuts for serving)

Remove stems from chiles and add to food processor/blender, until finely chopped.

Transfer Walnut mix to a bowl and stir in Garlic, Parmesan, Oil, and 1 Cup Parsley. Season with Salt and Pepper.

Cook pasta choice in a large pot of boiling salted water, stirring occasionally, until Al Dante.

Drain, reserving 1 Cup pasta cooking liquid.

Return Pasta to pot and add the Pesto along with 1/2 cup pasta cooking liquid.

Toss, adding splashes of cooking liquid as needed, until pesto coats pasta and sauce is glossy.

Crush reserved Walnuts with flat end of a knife. Divide pasta among bowls and top with crushed Walnuts and little more Parsley.