i'm pretty sure i've seen nestle and carnation, but usually nestle. sometimes when they run out of something they will replace it with a temporary stock of something else (like on our last cruise they ran out of bottled water so starting using the
walmart house brand - they must have bought it in port!), so the carnation might have been due to a situation like that, as it's generally nestle. if you make it with hot water and then add a dash of milk, it stays warm but helps with the creaminess. i do that a lot at home when i'm low on milk and too lazy to run to the store.
not sure what ship you will be on, and they are not free, but the promenade cafe makes hot chocolate with milk. it's $3 or $4, but maybe you could get a large and split it between the kids. the patisserie on quantum and anthem also sell gourmet hot chocolates made with milk for around $4 that are fantastic. these are also all included in the royal replenish drink package, if you are looking at packages at all.