Seriously - why not simply drive the vehicle? Cars were made to run. The Murano was made for winters! Simply driving it once a week for 30 minutes or so could keep it running smoothly.
If you HAVE to store it (as opposed to driving), here's the procedure I use on all my seasonal engines (think motorcycle, boat, lawn mower, chain saw, etc.)
1. Fill the gas tank and stablize the fuel. Over the winter, water vapor may condense in the empty spaces in the gas tank. This can cause problems in the spring if significant amounts of water accumulate. Filling the tank minimizes water condensation. Gasoline is also a volatile mixture. It will degrade over time into a sludge-like varnish that will clog intakes and fuel injectors. Best way to accomplish both steps is to drive to a gas station, add the appropriate amount of Stabil or equivalent, then fill the tank. Following these steps will mix the Stabil in the gas tank. Driving home will then ensure that stablilized gas is in the lines and engine.
2. Wash and wax the car. This removes dirt, gum, tar, bugs and other stuff that can eat into the paint over the winter storage period. The wax provides a sealing coat to protect the painted finish. Also, don't forget about polishing the chrome grill and tailpipes too. A thin layer of clean oil will keep the chrome tailpipe covers from rusting. Be sure to also clean and dress the tires.
3. Move the car to the spot where it will be stored. Inside a garage is best - with a light cotton cover. Others have noted the importance of storing inside versus outside. I would agree that parking the car on grass would cause a quagmire in the spring, not to mention exposing the vehicle to more moisture and the elements (even with a cover).
4. Change the oil and filter. In addition to lubricating vital engine parts, oils capture and suspend contaminants and acids that are created as by products of the combustion process. Changing the oil ensures that you have removed any such contaminants in the old oil and will store the engine with fresh new oil. After changing the oil and running the engine to circulate the new stuff, do not run the engine again if you can help it at all. Some folks say to start the engine every few weeks during the winter. This only creates more contaminants and acids. Its better to leave the engine alone after this step - especially given the step 6. While your at it, check the antifreeze level and condition. Change it if necessary.
5. Change the air filter. As you drive, debris accumulates in the filter. Changing the filter before winter storage ensure you have a fresh clean filter for the spring season and is one less thing to worry about when the car is ready to come out of hybernation.
6. Treat the engine cylinders. Use fogging oil (available at marine supply shops) to shoot a thin coating of oil inside the cylinder walls. This will prevent rust from forming inside the engine over storage. While you're at it, check the spark plugs to make sure they look good. Use "anti-seize" when reinserting the plugs and torque to manufacturer specified values.
7. Remove the battery and take it inside. Place it on a trickle charge with float monitor. The Battery Tender is a good model. It will charge up the battery and turn itself into "monitor mode" after the battery reaches full charge. This ensures no overcharging. When the voltage drops (as it is likely to do over time), the Battery Tender will automatically maintain the charge necessary to keep the battery at optimal status. Taking the battery inside will keep it from freezing.
8. Inflate the tires and jack up the car. If stored for long periods of time, tires can develop flat spots from the weight of the car sitting on the same patch of tire over several months. Inflating the tires to a higher value will help minimize this (i.e., 40psi may be a good value). Ideally, you want to take the weight of the vehicle completely off the tires. You can do this by placing the car on jack stands at all four corners of the vehicle. This will eliminate the chances of flat spotting on tires and wear to suspension components.
9. Place a cotton cover over the car. This will help keep off dust as the vehicle sits over the winter.
Remember, over the winter, do not be tempted to start the car. This will undue much of what was done above.
Good luck.