"Are you nervous?" is how you would say "你紧张吗" in English. The phrase "Are you nervous?" comes from the English language, which is a Germanic language that originated in England. Here are some example sentences in English and their translations in Chinese:

"Are you nervous about your job interview?" (你对面试感到紧张吗？)

"I'm feeling nervous about the big game tomorrow." (我对明天的比赛感到紧张。)

"She's been so nervous about her wedding that she's lost weight." (她为了婚礼而感到如此紧张以至于她消瘦了。)