Car insurance in Ireland

Yes, plenty of people have (myself included).

It's the same as with using it anywhere: you must decline all optional insurance offered by the rental agency (if you don't, the coverage from your card will not be valid). You must pay for the car rental (all of it) with the card.

Despite what you will hear from many people (including many well-intentioned folks and also people who have a vested interest in spooking you, like they guys who want to sell you their own insurance) there's nothing unique about Ireland (or Italy) that invalidates the insurance provided by that credit card. Call Chase and ask them (always do this before counting on the insurance provided by your card); Chase will tell you the same thing.

Do drive carefully on those impossibly narrow roads where we drive on the "wrong side". THAT is real.

Make sure that you understand how Chase is going to handle it for you. Do you pay and they reimburse you or will they stand in your place and pay the rental agency directly? What documentation is Chase going to require? Also, make sure exactly what is covered / not covered including items like wheels, tires etc.

there's nothing unique about Ireland (or Italy) that invalidates the insurance provided by that credit card

Well, unless the card specifically excludes those countries from coverage, all cards have some exclusions, (I doubt anyone covers Ukraine at the moment, Iraq, Israel, and other countries are also commonly excluded) you just have to verify that your card does cover the country you are traveling to. For that, you can start with Chase, but may need to speak with the company actually issuing the insurance, I would be wary taking a script reading customer service rep at their word, in fact, it is often recommended to have Chase issue a letter stating coverage and amounts, some rental agencies may ask for it. As the poster above stated, also understand what you need in order to file a claim. Getting a document, from Ireland, weeks after you get home, is no fun.

Also, while you must refuse any optional insurance, realize that liability insurance is required and usually an additional charge on the rental. Some confuse refusing "all" vs "required" not understanding what is required.

The rental company will likely want a written assurance that your card covers Ireland. The card companies are all quite adept at emailing a confirmation to you - wait until less than 30 days before your rental. I doubt if any card will "stand in for you". You'll have to foot the credit hold for any loss until your card company gets info and negotiates the payment. My Costco Visa (Citi) gets you off the hook within 30 days (I know from experience). Hertz and associated firms charge extra to "allow" you to use your card insurance (of did last year in Scotland L7/per day).
I've used my card insurance for five Ireland trips and four Scotland trips with zero issues (except one boo-boo on my part). I had a flat last year and they would have paid for that, but I misplaced the receipt (and it only cost me $80 total for the tire and mounting).

Thank you for your responses! Appreciate it!

FWIW, another RS poster has recommended a relatively new car retal agency in Ireland which includes a comprehensive insurance cover, including tires and the windscreen, in their already competitive pricing. It's called New Way and might be worth a look.

I got Rentalcar.com or Rentalcover.com car insurance last August when I took a solo trip to Ireland. It was offered when I rented my car. It wasn't part of the rental car company but an independent company. It cost me about $200 for a three week rental.
Guess what. I wreck the car crossing a one lane bridge two blocks from the rental agency in downtown Dublin. I get too close to the left side of the bridge and damage the front wheel and tire. I then change the tire myself and damage underneath part of the door panel when I jack the car up. Oh yeah and when you don't buy the car insurance from the rental car company they hold a $5000 deposit. So they are getting their money no matter what.
So now I've done about $2500 damage. I have never damaged a rental car before so I'm worked up for the next three weeks not knowing if this was going to be a hassle to make a claim and the get paid.
Well it all worked out in the end. I got back, made a claim, sent in the required information and was paid for the claim a couple weeks later.
It was the easiest claim I've ever made. And anther great thing was the $0 deductible so I wasn't out anything.