Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Mitchell Mark Nass, O.D.

Optometrist in Fort Defiance, AZ · enumerated 2006 · practices at Fort Defiance Indian Hospital Board, Inc.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1609936558

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Registry record

Entity type Individual (Type 1)

Name Dr. Mitchell Mark Nass

Credential O.D.

Sex Male

Practice address Fort Defiance, AZ, 86504

Phone (928) 729-8000

Enumeration date Dec 11, 2006

Last updated in NPPES Feb 18, 2026

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

152W00000X Optometrist Eye and Vision Services Providers · License 35433 (CA) Primary

152W00000X Optometrist Eye and Vision Services Providers · License OPC1771 (FL) Secondary

OD · Doctor of Optometry: A licensed optometrist providing primary vision care, eye exams, and corrective lenses. About the OD credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What is the NPI number for Mitchell Nass?

The National Provider Identifier (NPI) for Mitchell Nass is 1609936558, a Type 1 (individual) record in the CMS NPPES registry.

Where does Mitchell Nass practice?

The practice location on file with NPPES is in Fort Defiance, AZ. Providers can have multiple locations; NPPES lists the primary practice address.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-02-18.