I imagine this glitch is kinda niche, since the Sleipnir Rider's World Tree skill lets you conserve staff uses with Dex% chance. However, can be consistently done with the right preparation.
First, your staff user must have a weapon that they can equip. Unequip this weapon and Arrange the Nodus so it's before all of their weapons.
Next, your staff user must Level Up after using Nodus. If you watched the duping glitch, you probably know why.
When ready, have your staff user cast Nodus on your allies with depleted Engage meters. Your staff user will Level Up, but you'll notice Nodus hasn't broken.
If you check your staff user, this is because they've automatically swapped to their equipped weapon. Presumably, the swap happens before the game checks the staff uses.
Note: This method also works for Fortify, since it also affects all party members. I don't think it works on other staves, but you're welcome to try.
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