The regenerative effect is known to be the main reason to cause chatter, which is a self-excited vibration that can jeopardize productivity in turning and boring operations. The regeneration in the chip thickness is related to chip modulations and the wavy surface produced during successive machining revolutions. However, simpler models that do not account for this regenerative effect can produce good results when compared to experiments, especially when the chaotic motion that occurs during nonlinear chatter is being analysed. The purpose of this paper is to study the impact that the added regenerative effect can have in such scenarios. To do so, phase-planes, spectra and time histories for two different models are going to be presented and its differences highlighted. The models are studied in three different situations: before the chaotic motion appears, and therefore before chatter instability begins; during chatter; and after the chaotic motion ends.