The message meant to say Good Fortune, but Rosetti was too insecure and paranoid, thinking it was something bad because he couldn't understand it. But being Italian, it's odd that he hadn't caught that. I think Nucky was being sincere with this, but you never know.
I heard an interesting theory regarding Nucky and Billie, in that she helped distract him from thinking too much of what he did to Jimmy, because I do think he feels remorseful about that, and that without her around, it was starting to get to him.. I think the bacon is something he associates with Billie and smelled it even when she wasn't around because of his need for her. In a sense, she was like his drug. At first, I thought Nucky was having a stroke, but I later realized he just looked really distracted.
I have a hunch that something will happen to Billie later on, in which she'll need the care that Margaret is trying to get the hospital set up with. It would be an interesting twist considering Nucky's been against it, especially if it's something that could save her life.
Overall, I thought the episode had an odd narrative and pacing. Much of it felt disjointed.