Nico showed up at some point to kind of quickly wish her a happy birthday and give her a cookbook. It's a very sincere gift because he figures if she's going to try to cook, she might as well have some recipes, and he thinks she enjoys the kitchen, so he thought she might enjoy a cookbook. It's wrapped in brown paper with her name on it in a deliberately trying not to be messy scrawl. He might not stay too long, but he'd try to be polite and not immediately bail after handing over the present. Just kind of lurk in the background and people watch.