<PAGE>
EXHIBIT 4.1
(On J. J. Kenny Co., Inc. Letterhead)
August 11, 2000
Nuveen Investments
333 West Wacker Drive
Chicago, IL 60606
Re: Nuveen Tax-Free Unit Trust, Series 1186
Gentlemen:
We have examined the registration statement File No. 333-43190 for the
above-captioned trust. We hereby acknowledge that Kenny S&P Evaluation Services,
a division of J. J. Kenny Co., Inc. is currently acting as the evaluator for the
trust. We hereby consent to the use in the Registration Statement of the
reference to Kenny S&P Evaluation Services, a division of J. J. Kenny Co., Inc.
as evaluator.
In addition, we hereby confirm that the ratings indicated in the Registration
Statement for the respective bonds comprising the trust portfolio are the
ratings currently indicated in our KENNYBASE database.
You are hereby authorized to file a copy of this letter with the Securities and
Exchange Commission.
Sincerely,
Frank A. Ciccotto
