Can i applied B-2 visitor visa for my wife to visit us ? it will approve or not ?

If you are a US citizen or a permanent resident, you must sponsor your wife for a green card, not a visitor's visa. Please see

If you have LPR status or a US Citizen there ill be a high threshold for her to prove she does not have immigration intent when she applied for the B2 non immigrant visa.

Firstly, you cannot apply for a B-2 visitor visa for your wife, she must do it herself. She will need to show that her visit to the U.S. will be temporary. She will need to convince the consular officer that she will depart the United States after her visit. It is difficult to determine whether a consular officer will approve a visitor visa application. Good luck.

A B-2 visitor visa requires "non immigrant intent". Since her spouse is in the United States, it will be assumed that she will want to stay. You will have to submit evidence that she intends to return to Nepal. Are you a U.S. citizen? A lot more information is needed to know what other options she would have - including how long she wants to come, your status, and her employment desires.