I am the executor to a life insurance fund left to my niece and nephew ...I do not want to be executor ..

You are not required to accept a nomination to be an executor (called a personal representative in Colorado) but you are required to lodge the Will with the district court in the county where the decedent died. If the Will needs to probated, (not all Will require probate) and does not nominate an alternate personal representative you can request the Pubic Administrator for that district to serve as Special Administrator in the Estate. If the Will does not need to be probated because the decedent's estate is less than $50,000 and the decedent did not own any real property, the heirs can collect the assets with Small Estate Affidavit. If the insurance policy names beneficiaries, then they can collect directly from the insurance company, typically by provided a death certificate and filing a formal claim. If the insurance policy names a trust and you have been nominated as trustee but you do not want to serve and it does not nominate anyone else as trustee, you can file an action in district court to ask the judge to appoint a trustee. Many Wills in Colorado have a provision that says that if the intended beneficiary is under a certain age or in the opinion of the personal representative in under a disability, the personal representative can hold and administer the bequest for the beneficiary.