Despite its struggles, this business should be on your investing watch list.I'm sure most readers are familiar with Nike (NKE 0.25%). The leading sportswear business, which sells popular apparel and sneakers, has a global presence. And it's been atop the industry for many decades. But Nike has been dealing with some major challenges, which revealed themselves recently when the company reported its latest financial results. As of this writing, the consumer discretionary stock trades 58% below its peak price. ...