Is there any non-dairy (or chalav yisrael) substitute for Carnation Instant Breakfast?
First and foremost, if this is for someone who needs liquid nutrition, you must check with a nutritionist before trying something different. Saving a life trumps kashrut.
Additionally, many rabbis who normally require chalav yisrael will allow non-chalav-yisrael for someone seriously sick (even if not life-threateningly so). Or as the TV ads say, "ask your rabbi if Carnation is right for you."
But to answer your question: There's probably something in Israel, but I don't know how you'd find it.