LEAVE THEM ALONE.
Hummingbird nests are made with extremely strong, extremely stretchy spider silk, and the nest will expand as the nestlings grow. By the time they seem to be “outgrowing” the nest, they’re almost ready to leave it permanently.
By second-guessing the mother hummingbird and Mother Nature, you risk injuring or killing the youngsters in addition to violating federal and state laws that protect wild birds.
Unless a wild animal is in obvious distress or danger, it is best not to intervene without consulting a wildlife rehabilitator or other wildlife expert.
See also: “Rescuing” baby hummingbirds