Usually when I make šnicla, I’ll have at least one piece left over and unless I have access to an oven (not a microwave!), I’m not too much a fan of the next day taste.
But! I found that making a sandwich with homemade garlic scape pesto, as well as fresh cheese, tomato, and lettuce, it makes a delicious work lunch my husband. He literally rests it on top of a toaster at work (they don’t have a toaster oven) and that apparently heats it enough that the chicken doesn’t taste rubbery and the vegetables don’t get soft. I’m taking him on his word since I don’t eat sandwiches (since I was a kid I hated them. I need to have a real meal, every meal), but if you are making it at home, I would just heat the šnicla in a toaster oven at 200 degrees for a few minutes and then make the sandwich.