Yes, I did read it! No real spoilers under the cut, bc the short answer, about Nicolas, is No :- 

Characters refer to Nicolas a few times but he’s not around. There is the theory out there that he faked his death and may yet reappear in the next book, though!

Lestat still has the letters Eleni wrote to him about the Theatre, and he writes about them: “the letters that told me of its prosperity with the Paris audiences, of Armand’s governance, and of the death of my Nicolas, my second fledgling, my only mortal friend, and my greatest failure.” 

;A;