A transmission electron microscope (TEM) fitted with a nanomanipulator for in situ mechanical deformation of nanobelts is reported. Nanobelts of beta-Ga2O3 were grown by the vapor transport method from gallium metal in an argon gas flow at 1223 K. A single 2.3 mu m wide, approximately 200 nm thick and tens of microns long belt was deformed by direct contact with the manipulator probe. Deflections of up to 180 degrees with a radius of 2.5 mu m were recorded without fracturing. A series of TEM diffraction patterns collected during belt deformation was observed to distort as well. In addition to the distortion of the monoclinic belt diffraction pattern, satellite spots were observed through belt deformation. Analysis of the deflection in pre-existing spots reveal simultaneous lengthening and contracting in measured planar spacings. The lattice deformation results in the lattice constants c and a having two simultaneous values for any given diffraction pattern. The maximum simultaneous deformations in c are measured to be 1.13 +/- 0.112 and 1.63 +/- 0.162 nm. Lattice constant a behaves similarly with values 0.51 +/- 0.02 and 0.79 +/- 0.03 nm.