Yes, it would, except that "nave" here presumably means "nave lateral", and in English that is "aisle"; the word "nave" in English denotes either the whole main body of the church or to what is called the "nave central" in Spanish. Since "de la epístola" can only apply to a nave with lateral aisles, the word here is "aisle". Or you can say "the Epistle side of the nave", using "nave" in the sense of the whole main body of the church, particular in churches without side-aisles. But here it probably means "nave lateral".

https://en.wikipedia.org/wiki/Epistle_side
https://en.wikipedia.org/wiki/Nave
https://es.wikipedia.org/wiki/Nave_(arquitectura)
https://en.wikipedia.org/wiki/Aisle#Church_architecture

"Blessed Sacrament Chapel / Epistle Aisle"
http://www.armagharchdiocese.org/st-patricks-cathedral/

"The six windows on the Epistle Side of the nave recall some of the parables of. Jesus"
http://www.trinitycathedral.org/sites/default/files/sites/de...

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Note added at 22 mins (2015-09-01 20:55:26 GMT)
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From the Wikipedia article on "aisle", which links to the Spanish article on "nave lateral":

"In church architecture, an aisle (also known as an yle or alley) is more specifically a passageway to either side of the nave that is separated from the nave by colonnades or arcades, a row of pillars or columns."
See illustration on right of page with the aisles shaded in grey.
"Confusingly when discussing overall design, architectural historians include the central vessel in the number of aisles. Thus the original St Peter's Basilica in Rome, Milan Cathedral, Amiens Cathedral and Notre Dame de Paris are all described as having five aisles, meaning they have two side aisles either side of the central nave."

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Note added at 26 mins (2015-09-01 20:58:52 GMT)
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So the translation here will depend on the structure of the particular church you're dealing with and exactly which part of it they're referring to. I could imagine that they might use "la nave de la epístola" to mean the Epistle side (the right as you face the altar) of a single nave without aisles, but in principle it seems to refer to a "nave lateral", separated from the "nave central" by columns, and if this is so, you should use the word "aisle".