Richard, the word "nasal" in this context does not mean singing "through your nose," a la some Country and Western singers. "Nasal resonance" means something quite different.

This is why I said that it is diffiicult to explain things like this in a post--without the possibility of demonstrating what is meant, which a good voice teacher would be able to do.

The concept of "nasal resonance" has to do with projecting the tone produced by the vocal folds into the natural resonating cavities of one's body, such as the sinuses (nose), as well as the mouth and throat.

Let me put it this way:   A guitar has not only strings, which produce the pitches and basic tones, but a resonating chamber (that big funny shaped box that the strings are attached to) which amplifies and projects the tone produced by the strings.

Same idea with the human voice.

But if your throat and general vocal mechanism is tense or constricted, the tone has no place to resonate and dies about six feet in front of you.

By the way, starting a singing practice or session with a couple of good yawns is a very good idea. Opens the mouth and throat, relaxes the larynx, and prepares your lungs to operate efficiently.

But understand the difference between "nasal" (as in "resonance") and "nosey."

Don Firth