President Bush announced his intention Tuesday to nominate former Maine Republican gubernatorial candidate Peter Cianchette of South Portland to be ambassador to Costa Rica, according to a White House press release. Cianchette now serves as a partner at CHK Capital Partners LLC, a private equity firm based in South Portland. He previously served as president of the Cianchette Group. A graduate of the University of Maine, Cianchette also once served as chief operating officer and executive vice president at Pierce Atwood Consulting. Cianchette lost to Gov. John Baldacci in the 2002 gubernatorial election and briefly sought the Republican nomination for the 2006 race before bowing out.