Parts of it. It is a collaborative effort between the defense and prosecution.
After the defense and prosecution in a Nevada jury trial have presented all their evidence and witnesses, they have the opportunity to submit jury instructions to the judge. Like it sounds, jury instructions are the guidelines and laws the jury must abide by when deliberating over what verdict to hand down. The judge reads the jury the instructions prior to closing arguments, and the jury takes the instructions with them into the jury room to refer to when they are deliberating.
Jury instructions are ultimately a collaborative writing process between the defense attorneys and deputy district attorneys, with the judge acting as the umpire. Each side writes its own instructions and/or copies favorable instructions from other cases in Nevada or similar jurisdictions. Each side has the opportunity in court (outside the presence of the jury) to object to each other's jury instructions, and the judge makes the final decision over which jury instructions get included.
Typically jury instructions include the legal definition of all the crimes the defendant is accused of, and these definitions include the elements of the offense. Jury instructions also include instructions on how to weigh evidence ("beyond a reasonable doubt") and how to decide whether a witness is credible or not. Juries may then ask the judge for clarification if they do not understand the jury instructions. (Read our article about bench trials versus jury trials in Nevada.)