Nylon Insert Nuts DIN985 also known as a Nylock, has a nylon collar insert and are sold in packs of 10.
HCHAWA0088: M3 A2 Stainless Steel Nylon Insert Nut DIN985 (Set of 10)
HCHAWA0089: M5 A2 Stainless Steel Nylon Insert nut DIN985 (Set of 10)
HCHAWA0090: M4 A2 Stainless Steel Nylon Insert Nut DIN985 (Set of 10)