I read that Israel attacked Egyptian army camps in the Gaza strip in early 1955. Why did Israel attack Egypt and was this related to the nationalization of the Canal in any way?

The nationalization of the Canal was likely related, but I'm not going to speak to that. I'll discuss the raid by Israel on the Egyptian army camp on February 28, 1955, known as "Operation Black Arrow". The raid came after a few years of back and forth strikes by Israel and Egypt. The two were still technically at war, despite the armistice, and raids into Israel and vice-versa were common. The raids into Israel were often conducted by Egyptian forces or sometimes by Palestinian-supporting groups, though the latter were not usually sanctioned by Egypt (as they were more heavily supported in Syria by comparison).

Both sides had already been tense, and were set on what appeared to be a collision course towards another war because of these raids. The destabilized border led both to think the other had to be "punished", which meant tit-for-tat attacks and operations were the norm. This was particularly true following the Lavon Affair, where a group of Israelis attempted to create a false-flag attack in Egypt, which was botched and the Israelis were caught. They were operating without the consent of the Israeli Prime Minister, and it led to a huge scandal in Israel.

The immediate spark for Black Arrow was an infiltration by Egyptians. In the week before Operation Black Arrow, a team of Egyptian intelligence scouts snuck into Israel, spied on defense facilities, and shot an Israeli cyclist on a road near Rehovot. There were also reports that Israel tracked some of them down and killed at least one of the operatives. Israel decided to launch a retaliatory strike, and a powerful one to try and deter Egyptian activities of those sorts, leading to the attack killing 40 Egyptian soldiers (8 Israelis were killed) in an attack on an Egyptian army camp, a train station, and Egyptian relief column.

This all led into the obvious conflict between Egypt and Israel in the Suez Crisis. Much like the Six Day War, the conflict was preceded by tit-for-tat attacks between the avowed enemies, and immediate retaliation was seen as response for a previous attack in the cycle of violence.