My parents used "Klim," the 1940s-1950s equivalent of Nido, and I hated it! It was impossible to get the lumps out. They insisted I drink several cups per day. Much of it got surreptitiously dumped behind bushes at the periphery of camp! I finally put my foot down (at age 13) and insisted on no more Klim, even in cocoa. Gross stuff!

To this day, I use dried nonfat milk. For that matter, I use nonfat fresh milk, too. I loathe the taste of milk fat!

Even with dried nonfat milk, it will curdle/lump if mixed in too-hot water.