There are a couple of options for "way" (translation suggestions from the linked L&S):
- Via: way, method, manner (II.A); the right way, the true method (II.B)
- Ratio: conduct, procedure, mode, manner, method, way (II.B.1.c.α–β)
- Ordo: a regular military formation (II.B.1)
- Modus: way, manner, mode, method (II.B)
- Mos: manner, custom, way, practice
Depending on what aspect you want to emphasize, any of these will do.
To me modus or ratio feels too clinical and cold.
Perhaps ordo is more about staying in line than following the correct customs, but it makes sense in both more and less literal meanings.
My preference is mos or via, with a slight preference for via if it is not just a way to be but also a way to go forward.
When translating the whole catchphrase to Latin, it is good to make note of the English definite article "the".
It is not emphasized in the delivery in the series, but replace with "a" and the meaning is changed.
Latin does not make the distinction, so it might be best to add something to replace the article, like hic est mos noster or haec est via vera.
Given the way the phrase is used, I think it need not be a full sentence.
In English "the way" would probably be too short, having only two syllables, but I think a plain mos noster or via vera work well.
A different echo?
In The Mandalorian the catchphrase "this is the way" is often often used so that one says it first and then others reply with the same.
It might work well to modify the response, e.g. via nostra — via vera.
Goal and context
The question is, as usual, what it is that you want to achieve.
If you want to reach the same dramatic effect when retelling the story in Latin, then I would probably go with my last suggestion.
If you want a faithful translation so that people who know the series and Latin will recognize it, then I would pick something else.
I don't think there's a good translation that is simultaneous faithful in literal content, nuance, and dramatic effect.