One does not project from the diaphragm, nor from the chest cavity, nor from the nasal “mask.” All this physical activity plays a role in the voice being projected, but projection is not something that one does by accessing a certain localized area.
When 1, 2, and 3 are happening well, we get resonance as a bonus due to all being in sync. It is this resounding that causes the voice to be projected without us having to do anything but focus on the essentials of registration, vowel, and moving air.
Projection takes care of itself without any extra energy expenditure!