Yes you can, it's made easier in LV7 due to NI no longer supporting the old serpdrv driven serial VIs (which you could use instead if you want to avoid the VISA install...), but it's there in LV6 as well. On your LV CD you should find an installation set for the VISA RunTime, or you can download it at:
http://digital.ni.com/softlib.nsf/webcategories/85256410006C055586256BBB002C0E91?opendocument&node=132060_US
You can then make the installation of your application run a silent installation of VISA when it's finished:
Read how to make the VISA install "silent":
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/0730a66245e6808086256ca8006e2183?OpenDocument