Working over an arbitrary field of characteristic different from 2, we extend the Skjelbred-Sund method to compatible Lie algebras and give a full classification of nilpotent compatible Lie algebras up to dimension 4. In case the base field is cubically closed, we find that there are three isomorphism classes and a one-parameter family in dimension 3, and 10 isomorphism classes, 7 one-parameter families and two 2-parameter families in dimension 4
Ladra et al. (Thu,) studied this question.