This past year has been an excruciating one for investors in NuStar Energy (NYSE: NS), which has tumbled nearly 60%. That deep dive has driven the pipeline and storage terminal master limited partnership's distribution yield up into the double digits. While a payout that high usually is a sign of trouble -- and it was for NuStar last year -- that no longer seems to be the case now that the company has outlined its new way forward.One of the issues that eroded NuStar's value over the past year is that distributable cash flow took a hit, dropping from $365 million in 2016 to $258 million in 2017.