Can I use sweet condensed milk instead of milk powder?

Condensed milk is a bit sweetened as it is reduced to almost half the amount with lots of sugar in it. On the other side, the milk powder is exactly like milk with no added sugar. So both forms of milk have different properties and can be used as a substitute, depending upon the recipe in which you are going to use it. Plain milk is better substitute of milk powder rather than condensed milk which is costly as well as less suitable as a replacement.

Sweetened condensed milk contains quite a bit of sugar, and it will also bring extra liquid. It is basically whole milk, with the water reduced to about a 50/50 mixture of sugar and milk. So it would be much sweeter than dry milk, which is usually dehydrated skim milk. That would give you a much sweeter product than intended. It might be suitable for sweet rolls, but not the dinner table. It also brings a small amount of liquid with it, so you would need additional flour to absorb that as well. All things considered, if you don't have dry milk powder, in this instance I would recommend just using plain milk, and adding in the extra bit of flour. That would replace the milk solids the dry milk powder brings, without added sugar that you don't need.