While combat exists in Nobilis, it is generally frowned at because of the deep social interactions the game encourages. As such, references of combat in Nobilis are short (if not almost non-existent) since most conflicts can end instantly with a single display of power.
Combat in Nobilis is turn based. Whoever engages first in combat starts first (socially violent characters often attack first and ask questions later), be this the players or their foes. In each turn, one side of the fight acts while their opponents wait. On their turn, characters can move freely on the battle field.
If using a square grid and miniatures to visualize combat, each character can move a number of squares per turn equal to their Aspect Level plus three (and in case of having a superior attribute that favors movement, use the one with largest value).
After or before movement a character can perform a single action. Attacking with weapons, using a gift or a miracle and using a item (is your campaign requires them) counts as an action. After the action is announced but before it happens, any opponent can "counter" that action by using a action themselves, sacrificing any action they could use on the following turn.
Each action can only be attempted to be countered once, and there are several factors that favor a successful counter which depend on how imaginative the counter-action is. If the action is not countered then it happens normally and its effects are measured. Combat, in essence, is a match of wits and strength, and like any real-life combat, outside influences can change the outcome instead of just being an event of chance. Physical attacks like swords and bullets can be absorbed using armor or body resilience (it's hard to damage an immortal) while Miracles, Gifts and other sources of magic can be protected with a high Auctoritas rating. In theory, a high value of Auctoritas or armor couldn't possibly be overcome, making strong characters virtually immortal even though in essence they are mortal.
Each action has a Penetration Value which can vary depending on the circumstance. In the case of weaponry, for example, each weapon has a attribute requirement depending on the nature of the weapon. "Excalibur, the sword of the Kings" would be an Aspect requirement weapon and the "Hermes' Staff" would be a Spirit requirement weapon while the "Lexicon of the Truename" would be an excellent weapon for the Domain of Words. Using the imagination in building a weapon is essentially and also a weapon can be built as a character just like an Excrucian Focus.
Penetration is determined by any miracle points spent above the amount required to perform the miracle. For every additional miracle point spent on a miracle, it achieves one point of Penetration.
In order for an action to affect the target, the Penetration must be at least equal to the Auctoritas or armor value, depending on the situation and action used. If the Power of Fire invokes a fireball using a Level 4 Lesser Creation Miracle and then spends 2 additional Miracle Points to overcome the target's Auctoritas value of 3 then the total Penetration of the fireball would be 2 and the it would slam into the other Power's Auctoritas, having no effect on the Power himself. If 3 points of Penetration were used by spending an extra 3 MP instead, then the Penetration would equal the other Power's Spirit level and the Miracle would affect them normally.