If I have a LtLH in play, and my opponent has an unactivated Inkmoth Nexus, am I able to use LtLH's +1 ability on the Inkmonth Nexus such that, should my opponent activate the Inkmonth Nexus, it will instantly die? Or am I unable to target the Inkmoth Nexus with the +1 ability as it is not a creature?
Liliana's first ability can target Inkmoth Nexus only while it's a creature (C.R. 114.1c, 601.2c). However, targeting a creature is optional with that ability since it uses the phrase "[u]p to one target..." (C.R. 601.2c; see also C.R. 107.1c).
EDIT (Mar. 3): Added rule citation.