Chimera has no builtin ability to perform trajectory smoothing, but it can be done with a Python script.  You can find such a script on this page: Scripts – Chimera.  Look for "smoothMD.py​" (not "smooth_md.py", which is the same script but for ChimeraX).  Make sure to look at the chimera-users message linked next to the script, which describes how to use the it.