As you have asked about the Municipal Corporation in Nilgiris district in Karnataka, I am giving you information about it, check below for the details

I want to tell you that there is not any Municipal Corporation in Nilgiris district.

The Nilgiris District Comprises of six taluks viz

Udhagamandalam,
Kundah,
Coonoor,
Kotagiri,
Gudalur and
Pandalur

These taluks are divided in to four Panchayat Unions viz.,
Udhagamandalam,
Coonoor,
Kotagiri and
Gudalur

It also has two Municipalities,

Wellington Contonment and
Aruvankadu Township.

The District consists of 56 Revenue Villages and 15 Revenue Firkas.
There are two Revenue Divisional in this district viz.,
Coonoor and
Gudalur

There are 35 Village Panchayat and 13 Town Panchayat in this District.