If the chick stumbles some more or seems sleepy on its feet, try warm sugar water dripped onto the side of its beak.
Poultry Nutri-drench is especially helpful in these cases of a weak chick. Everyone should have a bottle. It's a life saver.
Can you identify the chick you saw stumble? Can you keep an eye one it for a bit to see if this was just a stumble or if this is something such as weakness and failure to thrive?
Are you in the US?