Does the nose-up attitude of a jet make it more difficult to land than a turboprop?
You're asking, I think, two questions. The first in the title is very general; the second in the text relates to control as affected by aircraft pitch on the approach. The answers to both are going to be somewhat opinion based as well as depending on which turboprops and which jets you're talking about.

My thoughts are based on the following turboprops: King Air A90, Swearingen SA-226 and 227, Fokker F-27; and on the following jets: Cessna Citation 500, Boeing 727-100, and Boeing 747-100/200.

In my opinion, there is no general practical difference in the difficulty or ease of approaches and landings based on whether you're in a turboprop or a jet or what your pitch angle on the approach is. Some might say that a nose down attitude is going to give you better visibility. However, I never found that lack of visibility over the nose was a problem.

There are differences in the characteristics of turboprops and jets that make the one or the other the better approach and landing vehicle in certain circumstances. For example, if you need a quick descent, you can flatten out the pitch of a turboprop and get a lot of drag, more if you move into beta. For jets, the engines are always going to be producing some forward thrust (although I seem to remember the DC-8 allowed idle reverse in flight).

If you have a crosswind, the heavier the aircraft and the higher the landing speed, the easier it will be to handle the cross wind, and transport category jets in general are heavier than turboprops. Also, in a crosswind, a high wing is considered a liability, and there are a lot of high wing turboprops.

I guess what I'm saying is that individual aircraft and circumstances outweigh differences between turboprops and jets insofar as approach and landing is concerned.

The hardest and easiest aircraft I flew insofar as getting a good touchdown were both jets: the hardest being the 727-100 and easiest the 747.

The most flexible insofar as the approach was concerned were the SA-226/227. You could fly the approach clean at near-jet speeds and then slow down very quickly on short final. KSFO controllers back in the 1980s used to appreciate our ability to fit in. Or they could bring us in on a close-in downwind and then have us dump it for a well-timed turn to base and then a very short final.

---------- Edit for additional information

@JanHudec pointed out that turboprops have a faster response to power changes than jets. That's true, though in day to day flying, you plan for what you have. Obviously, though, in an emergency situation that required additional power, the turboprop would enjoy the advantage.

The difference in response to adding power is not as great as it used to be. As I remember, when the 727 first came out, there were a couple of incidences of 727s touching down slightly short of the runway because of the time required for the engines to spool up. The figure that sticks in my mind is that for those first engines, the time from full idle to full power was 7 seconds. Boeing fixed the problem by putting in a flight idle and a ground idle. The flight idle kept the engines spooled significantly higher than the ground idle. That involved no change to where you placed the thrust levers. You brought them all the way back. If you were still in the air, that wouldn't spool the engines all the way to full idle.

The 747 engines reacted very quickly, much more so than the 727 even with the flight idle setting. I remember two instances in the 747 in heavy gusting crosswinds where I used a lot of power at the last moment. In the 727 those touchdowns might have been a lot harder? In a turboprop maybe a little less hard?