No, they will not fit. They are a 5X4.75 bolt pattern.

 

I think if you could find some adaptors from 5x115 to 5x4.75 they'd work. Personally I've never favored using wheels that aren't for the true bolt pattern of your car. I think they'd look great if you could make them work, however, the backspacing of those along with spacers would probably put them way out past the fenders and wouldn't look so great IMO.

Your best bet is just to find a different type of rim that comes in 5x115 with proper backspacing

 

They make aftermarket 20 IROCs that will fit just gotta buy the right bolt pattern

 

There r iroc replica wheels with different bolt patterns & fwd or rwd configuration

 

Do theses iroc replicas stick out? and will they work if your monte carlos is already lowered? 20's on a 2006 monte?

 

Here is a link to a space that might possibly work but when you do this type of modification they sometimes look a bit strange?. Might stick out to far? I put Monte Wheels from and 02 onto a 99. The patterns were the same but the offset was different so I just needed the spacer for the front to make it work and not rub on the brake caliper.
The way they work is you bolt them onto your car using the existing lug bolts and the lug nuts that they provide snug them to the Torque specs. then slide the wheel up to the new bolt pattern and lug nut it up to the Torque specs. You may need to purchase some lug nuts also. Hope that helps. The IROC wheel is kool hope that helps some.

wheel spacers 5x4.75 to 5 x 115 | eBay