In the Morgul Vale adventure deck, the Nazgul of Minas Morgul says:

Reduce any amount of damage dealt to Nazgul of Minas Morgul to 1.

The Morgul Bodyguard says:

Any damage that would be dealt to a Captain enemy is dealt to 1 Morgul Bodyguard instead.

We couldn't come to an agreement on whether the damage redirected to the Bodyguard would be reduced to 1 by the Nazgul before the redirect or if the Bodyguard would receive full, unreduced damage.

My contention is that the Nazgul only reduces damage that is dealt to it, while the bodyguard's ability interjects before damage is dealt (damage that would be dealt to the Nazgul is redirected; since it is never dealt to the Nazgul, it is not reduced to 1).

The other opinion was that the Nazgul reduces the damage to 1, then is assigned damage, which the Bodyguard takes instead.

Any clarification on how this is intended to work? Does the bodyguard take full damage or reduced to 1 damage?

«would be dealt» and «dealt».

I'm not an english native speaker, but to me, the damage should be redirect before, and if it is really dealt to the Nazgul, it would be reduce to 1.

Yep with the way it's worded the damage is placed on the bodyguard instead so the Nazguls ability not does trigger

third this

I think that is up to the first player.
"If two or more conflicting effects would occur simultaneously, the first player decides the order in which the effects resolve." (Source: LOTR FAQ VERSION 1.6 -- 1/22/2014, (1.02) Simultaneous Effect Timing, page 4)

The conditional sentence "would be dealt" and "dealt" doesn't specifically include a meaning of before and after.

They could have written "Reduce any damage that would be dealt ..." without changing meaning and effect.

IMHO is better if the First Player can determine what is the best course of effects to follow for each situation he is in.

The conditional sentence "would be dealt" and "dealt" doesn't specifically include a meaning of before and after.

Well, that's not how I learned English... can someone confirm ? (native speaker if possible)

Native speakers often have poor insight into their own language.

From a grammar standpoint, "dealt" is just past tense, whereas "would be dealt" describes a future action that has not yet occurred (along the lines of "If Gandalf would be destroyed, return him to your hand instead" -- Gandalf never got destroyed, so we were describing a hypothetical future event).

You would not be able to construe these as "simultaneous" actions, since they must occur in serial order. It's not 2 simultaneous instances of damage. Either the Nazgul gets the damage first and reduces it, then the Bodyguard gets it... Or the Bodyguard gets the damage first (so it won't get reduced).