It is easy. You need a wide flat blade. I use a motorcycle tire tool, but a flat blade screwdriver would probably work. You stick it in through the slot in the top of the latch and pry the latch below about 1/8" to get the teeth to let go. I forget which way you pry but it will be easy to feel it move.
These plastic latches get old and have to be replaced every decade or so. I have replaced them on both of my '97s. They don't really break, they just stop holding securely and and they pop up when you hit a bump, which makes the radiator start to rattle around.
Unless other cooling system parts appear to have been replaced recently, you will like yourself better in the long run if you replace everything you touch in the cooling system while you are in there. That way you won't be draining the coolant and dismantling it again in a year. I recently sprung leaks in both of my 2004s - one in the water pump and one in the expansion tank. Both cars have a little over 100k miles. I replaced everything I touched, fan clutch, expansion tank, hoses, radiators, water pumps, thermostats and covers, everything. Now I drive with confidence (for the next seven years anyway). This is particularly critical if your wife drives the car because if she is like mine, she will not pull over until the car overheats so badly that it will no longer move.