Addendum to 'Étale dévissage, descent and pushouts of stacks' [J. Algebra 331 (1) (2011) 194–223]

Using Nisnevich coverings and a Hilbert stack of stacky points, we prove etale devissage results for non-representable etale and quasi-finite flat coverings. We give applications to absolute noetherian approximation of algebraic stacks and compact generation of derived categories.