Nathan told Nadir that his nerves would impact the horse's ability to carry them through the competition. In your own words, identify the case of the underlined pronoun as well as the antecedent to which it refers. If the reference is ambiguous or indefinite, rewrite the sentence to correct the error.

Your question is incomplete because you have not provided the underlined pronoun. Thus, the complete sentence is the following:

Nathan told Nadir that his nerves would impact the horse's ability to carry them through the competition.

Case: nominative

Reference: ambiguous

Sentence rewritten: After seeing that Nadir was nervous, Nathan told him that nerves would impact the horse's ability to carry them through the competition.      

Explanation:

The possessive adjective his functions as nominative case because the noun phrase his nerves functions as the subject of a verb. Besides, it creates ambiguity because it is not clear whose nerves it refers to - Nathan or Nadir's. As a result, it is necessary to rewrite the sentence to clarify whose nerves affect the horse's performance.

what is the context here? we need to know what story you're talking about : )

the correct order is:

you're your own worst enemy:

they're going to say what they say, but

their opinions aren't holding you

back. it's your self-defeatist

attitude that's keeping your work

from getting its due.