The Nibbia Chapel, located in the present grounds of the Evans Building, was a domed, octagonally-shaped building and is known so after Fra Giorgio Nibbia who was buried there. Its façade consisted of a large portal panel having the main door set within two clustered sets of Doric pilasters on each side.

The door's architrave was adorned with a marble plaque at the centre and topped by a broken rounded pediment. A thin cornice separated the upper section which was made up of a central light arched window set between two smaller clusters of pilasters and running scrolls. Above the whole was a triangular pediment.

The ossuary popularly known as The Chapel of Bones was a vaulted underground crypt, possibly beneath the Nibbia chapel, but could also have been in close vicinity, and is reputed to be still extant, where bones from a cemetery of those who had died at the Sacra Infermeria were placed in patterns and designs as mural decorations, hence its name. The Latin inscription on the single altar lamented the ephemerity of life and requested prayers for the dead.

The ruins of the Nibbia Chapel can still be seen within a cordoned area. This chapel was hit by aerial bombardment during the World War II.

Mepa scheduled the ruins of Nibbia Chapel and the Chapel of Bones as a Class B national monument as per Government Notice no. 276/08 in the Government Gazette dated March 28, 2008.