From your pic, the problem is the granite countertop, not the stove.
The small piece of granite along the back of the stove should not be there, the stove, per your pic, sticks out about an inch or more.

You’ll need to get granite along the back removed.
Not the fault of Costco.

No, it will not go smoothly.

Just have them raise the stove a little above the granite or at least equal to the height of the granite.
Plus, they shouldn’t have put a piece of granite in the opening in the back in front of the backsplash because this is causing your stove to be way too far out into your kitchen.
If you live south of 44 and have gas you will need a new gas line, they won’t install it using an old gas line.

No problem
 

If you're replacing the current gas stove with another gas stove, no problem. The old one will slide out, and the new one will slide in. The installer will turn off the gas valve, and hook up the new stove. They should also level the new stove.

If you're replacing a gas stove with an electric stove, you have to carefully cap the gas line and install a 220 volt plug. Unless you're really handy, call an electrician and a gas plumber.

The problem looks like the anti-tip bracket has to be adjusted, or even worse they used the existing one that may not fit your new stove. Figures it's Costco..... yeesh

My mother had a new stove "installed" by Lowes, and it was a terrible experience. They installed the knobs incorrectly and didn't level it.

My recommendation is don't let the installers leave until you check the level yourself and make sure the knob numbers match what the burner is doing i.e, if you set it to medium, make sure it is actually on medium and not high or low. Seems easy to notice, but it isn't. I would also check the oven controls as well.

FoPAA....so? how did it go?

Sounds like you are blaming your husband for crooked granite

So, as I have said it did not go well. To clarify we are replacing an electric stove with an electric induction stove. As far as the functionality I believe all is well, it’s the cosmetics that have me upset. Costco is returning tomorrow to see what can be done.

The stove appears to need a simple leveling and have the feet lowered to raise the stove for proper fit.

I would point out that it appears that the stove you selected (Samsung?) is about 29 inches deep as measured to the front of the oven door. My Whirlpool stove measures only 25 inches in depth. So, you have an extra 4 inches of depth. The controls and handle take up even more space. That is part of the reason that the stove protrudes several inches beyond the front of the base cabinet. Removing the small piece of granite at the back wall may help if the stove can be pushed back, but the stove will still protrude into the kitchen. I believe that it would require the services of a granite company to remove the granite piece.

Village Tinker is my Hero!!!
 

He came, he removed the granite from behind the stove, and now my stove fits like a built-in! Thank you, thank you VT!

of course not! .
 

Blame is too mild a term

Husband of fopaa, writing from somewhere in witness protection

Should be easy IF the new stove does not have a top which is wider than the stove and is designed to go over the edge of the countertop. We have granite tops which are taller than other solid surfaces and formica tops and we had to adjust the feet of the new stove.

Update, the problem has been solved. As pointed out previously there was an additional piece of countertop in the area of the back splash. Once this was removed and the joints cleaned up, the new stove fit in place as was expected. I want to thank the person that noticed the extra piece of countertop, when I looked at the photos again, I realized I had missed that. I took about 1/2 hour to remove the extra stone countertop, and clean the joints.