Can a hemi be installed in dodge nitro?

No, a Hemi engine cannot be directly installed into a Dodge Nitro. The Nitro's chassis, engine bay, and supporting systems (wiring, transmission, etc.) weren't designed to accommodate the size, weight, and power of a Hemi engine. It would require an extremely extensive and costly custom fabrication project, far beyond a simple engine swap. Such a project would likely be impractical and possibly unsafe.