The word
$w=[x_{i_{1}},x_{i_{2}},\ldots ,x_{i_{k}}]$ is a simple commutator word if
$k\geq 2,i_{1}\neq i_{2}$ and
$i_{j}\in \{1,\ldots ,m\}$ for some
$m>1$. For a finite group
$G$, we prove that if
$i_{1}\neq i_{j}$ for every
$j\neq 1$, then the verbal subgroup corresponding to
$w$ is nilpotent if and only if
$|ab|=|a||b|$ for any
$w$-values
$a,b\in G$ of coprime orders. We also extend the result to a residually finite group
$G$, provided that the set of all
$w$-values in
$G$ is finite.