The new trends for anomalous Nernst effect (ANE)-based thermoelectric devices require materials with large ANE values to realize the scalable generation of voltage. Recently, very large ANE values have been observed in single crystals of some novel magnetic materials. However, to allow work to proceed on developing ANE-based devices, these materials need to be produced in thin-film form, and to date, thin films have not achieved the same large ANE values as bulk materials. In this letter, we report a large ANE in a 50 nm thick film of ferromagnetic Heusler alloy Co2MnGa, matching the values achieved in the bulk material. By systematically mapping the thermoelectric transport properties, we extracted an anomalous Nernst angle in the range of 11.5% -14.2% at 300 K.