If your wife is lucky, she will not be asked any questions. Read Mkikuyu's thread 'Successful CP in Nairobi, Kenya.
I have not gone through the CP process yet, my interview is in two weeks. I have however read through a lot of threads on CP experiences in other forums. My examples of likely questions your wife may be asked are just examples, based on experiences of other people, married and unmarried who have gone through the CP process.
General Questions
She may be asked to provide an address in the United States where she wants your Green Cards to be mailed
How many times has she entered the DV lottery
When does she intend to travel to the US
Education
If she has a College degree she may be asked questions related to what she studied in college.
Work Experience
If she is employed, she may be asked how long she has been at her current job. What are her job duties? She may also be asked for a letter from her employer and some pay stubs/pay slips.
Marriage
How long she's been married. If she got married after winning the DV lottery the Consular Officer may ask for additional documentation as proof that your marriage is valid. Example: wedding pictures, joint bank account statements, proof of property titled in both of your names etc
Evidence of Support
If she does not have an affidavit of support(Form I-134)and is depending on her personal funds/assets. She may be asked questions related to the documentation she provides. Bank statement, title deeds, car titles/log books
I hope this helps.
Good luck!!