Caviar is just a generic term for fish roe. If a kind of fish is kosher, its caviar is kosher, as well.
Sturgeon happens to be a nonkosher fish we eat caviar from. (Although sturgeon is/was considered kosher by some, similar to the case of swordfish).
There is plenty of kosher caviar, which comes from species like salmon, whitefish, etc.
In fact, one can even buy Kronos-brand Taramosalata, a Greek caviar dip, under Kof K.
When I make these latkes, I purchase Kosher Black Whitefish Caviar with an OU from Marky’s. It is about $62 for a pound.
And, because latkes fried in goose fat and schmaltz are so unhealthy, I do limit them to Chanukah. I buy rendered goose fat from Aaron’s Gourmet in Queens, at $17 a pound, which makes this method of preparation far from economical, so it is a rare treat.
Originally, latkes were prepared in goose fat in the medieval days, and they were eaten with chrein.
I find the idea of compote with goose latkes to be better, though, since when people traditionally roasted goose, they would serve it with something fruity. Roast goose with a fruit compote is heavenly.