For every there is such that every non-abelian finite simple group and every finite symmetric generating set containing the identity satisfyThe proof applies the one-scale virtual nilpotence theorem below the diameter and then uses simplicity to eliminate both the bounded-index subgroup and the finite normal subgroup.
Every finitely generated group of polynomial growth of a group has a virtually nilpotent group structure. Applying the one-scale virtual nilpotence theorem gives a finite normal subgroup with nilpotent quotient; centralizing that finite subgroup produces a nilpotent subgroup of finite index.