The number of nodes in a hydrogen atom ground state is n-1, just by accident the same formula as for the particle between two walls. In hydrogen, nodes can be either radial or angular. The energy of hydrogen atom eigenstates increases with principle quantum number n and the number of nodes according to the formula shown under the figures. Again, more nodes means more waviness and higher energy. Radial nodes mean more energy exists in motion where the electron moves closer and farther from the nucleus.
Angular nodes mean the energy is stored in rotation of the electron around the nucleus.