The 47-year-old Powell was formally unveiled on Tuesday as the successor to Ian Millward and revealed that, after club captain Michael Shenton, the first player he spoke to on his appointment was Chase, whose future has been clouded in uncertainty for more than 18 months.
"I spoke to Rangi yesterday and he's fully committed to Castleford," Powell said. "I'm going to sit down with him tomorrow and have a longer chat but he's definitely got the club at heart. You can see with his performances that he's committed to the team and the club when he's on the field. He's a fantastic player who delivers a massive amount."
Castleford chief executive Steve Gill told Tuesday's press conference the short-term future of both England international Chase and highly-rated hooker Daryl Clark was secure, and Powell was encouraged by his brief conversation with the 2011 Man of Steel.
Powell, who has signed a two-and-a-half year deal after leaving neighbouring Featherstone at the weekend, insists he is unconcerned over reports of Castleford's financial difficulties and believes the team have turned the corner under caretaker coach Danny Orr, who is staying on as his assistant.
"I've every confidence the club is in a strong position moving forward," he said. "I don't see any issues, to be honest. There's been some fantastic work done recently and we're looking forward to taking that to the next level.
"Danny has done an outstanding job. I watched Sunday's game last night and the team looks really strong. Obviously they need to toughen up defensively but the team looks pretty stable to me at the moment. There's a really good foundation to start moving the team up the ladder."
Despite winning two of their three league games under Orr, the Tigers are only above bottom club Salford on points difference but are also only six points adrift of eighth-placed St Helens, and Powell believes a play-off spot is attainable.
"I don't see six points as a massive amount when you look at what Wakefield did last year," Powell said. "I'm not going to start making any massive predictions but I do believe the squad has got everything within it to be competitive in every single game and to get over the line in a lot of them."