He has the option of a three-year permanent move to the 2016 Swedish Cup champions
The 25-year scored 16 goals and made 11 assists last season to help Rangers win the Nigerian league and claim a Champions League spot.
"Moving to Europe is a big dream come true for me," Egbuchulam told BBC Sport.
"I thank God for the opportunity and BK Hacken for the platform to play in European football."
Egbuchulam's impressive form in the domestic league led to an international call-up from Nigeria manager Gernot Rohr for the 2018 World Cup qualifier against Zambia in October.
Nigeria forward Chisom Egbuchulam has joined Swedish club BK Hacken on a season-long loan from Enugu Rangers.