It depends upon the terms of the settlement. Have the settlement agreement reviewed by an attorney who can advise you what you may be entitled to and how to go about making a claim if you are entitled.
You need to provide more facts. If the settlement was community property, then legally you are entitled to half of it regardless of how she may have disposed of it (by will or otherwise). If the settlement was coming to her by way of a structure, then you need to determine the terms of the annuity. Many annuities expire at death, but some have a minimum term (e.g., 5 or 10 years). If the annuity were community property, then you need to determine whether she willed her half to someone else, created a "beneficiary designation" or "POD" on the annuity, or otherwise assigned away her interest in it.
This is legal information only and not meant to provide legal advice. Many issues that seem straightforward at first are often complicated by facts not revealed in a hypothetical posed by a member of the public. You should always consult directly with your attorney in order to ensure the issue is thoroughly discussed and that the proper course of action is taken.
I agree with the other attorneys. More information is needed. Is this a settlement that already paid out? Or is it in an annuity or other investment vehicle? Take all the documents you know about the settlement and discuss it with an attorney that can assist you.
As we must state: any information provided in this answer is not legal advice and your use of it does not create an attorney-client relationship.
Sign up to receive a 10-part series of useful information and legal advice about the divorce process.