First of Two is
always right.
I believe there will be another NF novel, eventually. PAD is pretty busy, from what I hear.
In March, the Mirror Universe NF will be visited, in "Mirror Universe Volume 2: Obsidian Alliances," a BIG TPB with three novel-length stories, one of which will be a NF story by PAD.
a blurb (from startrek.wikia.com) :
Also, on the schedule for this coming November is a PAD book, as yet untitled, that will be a TNG novel, part of the TNG anniversary celebration.
It won't have NF, as far as I know, but it will have... Borg.
Given that PAD's last Borg book, "Vendetta," even if non-canon now, was full of win, I'll definitely be getting that one.