The inscription is of a type associated with the Nizam of Hyderabad, Mir Nizam 'Ali Khan Asaf Jah II (d. 1803). I have only ever seen these on Char Aina, but yours is the same style of inscription. There is a Char Aina in the Met (29.158.165a,b, published in David Alexander, Islamic Arms and Armour in the Metropolitan Museum of Art, no. 15) with the same inscription and the date 1192/1778-9, as well as another undated Char Aina in the Khalili Collection. Runjeet Singh had one in a catalogue too
http://www.runjeetsingh.com/inventory/378/cuirass
I cannot read the numbers at the end of this, though it might be ۲۰, the number 20, for a Mughal regnal year. If that's the case, it would be the regnal year 20 of Shah 'Alam II's reign which would be 1192/1778-9. If that's the case, then the very last, worn part of the inscription might be the words سنه ۱۱۹۲ (
sana 1192 'year 1192').
The first part of the inscription reads
سرکار میر نظام علیخان بهادر
'Sarkar Mir Nizam 'Ali Khan Bahadur'