High temperature mechanics of nanomoulded amorphous metals was investigated by in situ nanomechanical testing. Nanopillars of Pd43Cu27Ni10P20 metallic glass were synthesized by thermoplastic forming and their stress–strain response was obtained concurrent with direct observation of their deformation behaviour. This allowed the measurement of mechanical behaviour from nanopillars and the corresponding bulk substrate with identical thermal history. A rise in elastic modulus was seen with increase in temperature for both the nanopillars and substrate, which was explained by diffusive rearrangement of atomic-scale viscoelastic units. The results provide fundamental insights into structural rearrangement in metallic glasses. © 2016 Informa UK Limited, trading as Taylor & Francis Group.