I make nucs like you suggested all the time. I just grab a few frames of bees and brood from a couple of hives and stick them in my new box. Sometimes I put the new box beside the ones I took the frames from. It always works but you must feed and make sure you have enough bees, brood etc. The way I understand it is that the field bees will return to the original hives but that the nurse bees will stay with the new brood. In that way, there is no need to take them miles away. They apparently realize quickly that none of them are at home so they get used to each other pretty quickly in their new home. Hard to say what happened to your bees but if there wasn't enough food, if there weren't enough bees/brood, etc you may have had a problem. Of course, remember the "bees are sometimes random" axiom also. Anyhow, what you did works for me and many pals all the time so you may be more successful the next time you try it.