Chest dominant mix is when you drag your mix up higher. It is a controlled shout and is much safer than a standard belt. Instead of pushing out, getting louder and raising the larynx (shout qualities), instead we use nasal and head resonance to amplify the sound. This gives you higher notes that sound like chest voice. It sounds like a belt, but it is not, and you are much less likely to hurt yourself doing this than with traditional belting.
Tips for belting:
Keep a narrow embouchure (mouth shape). You want to block airflow from the mouth so it doesn't escape too fast like a shout. This encourages resonance in the head.
Keep the tongue taller like when making the "NG" sound.
Focus on light compression of the cords, which can't happen if too much breath escapes. Use a constant airflow and maintain strong breath support in the lower abdomen.
Keep the larynx as stable and as neutral as possible.
This exercise is "hallelujah" on a descending octave scale (8-5-3-1).