Yes, I know the magic system for BRS and Nemesis ORE are completely different, but my players are rather fond of using magic points, and I haven't got time to examine evry spell from the CoC rulebook and convert them into Nemesis ORE with each spell having their own dice pool. So here's what we came up with.

Whenever a mythos spell is cast, the caster rolls Mind+Mythos. (Non-mythos spells could be cast using Mind+Occult.) In addition to the above dice pool casters can also add one or more die from a pool of dice using the Magic Trait listed below:

New Trait: Mythos Magic
Pre-requisits: Mythos skill
Cost: none
Notes: This trait allows the player to add one or more dice up to the limit of the character's Mind+Mythos in a day, when casting a spell.

e.g. Douglas wishes to cast "Fist of Yog-Sothoth". Douglas has a Mind stat of 3d and a Mythos skill of 2d, and so his player rolls 5d. To ensure a successful outcome, Doug's player decides to spend 2d from his reserve of 5d from his Mythos Magic Trait, so he now rolls 7d to cast the spell.

This dice reserve is refreshed every day - the player can choose when (e.g. at midnight, at dawn, at sunset, etc). The player can also spend pips to turn die from this Trait into expert die and later into trump die to reflect the abliity of more experienced magicians to produce more spectacular spell effect on a more reliable basis.

A similar Trait called Occult Magic operates in a similar fashion, except it uses Mind+Occult to calculate the dice reserve available to augment spells cast.