Retail stocks including Nordstrom Inc. JWN, -3.45% (down 2.1%), Kohl’s Corp. KSS, -3.92% (down 3%), Gap Inc. GPS, -4.91% (down 3.3%) and Macy’s Inc. M, -4.84% (down 2.3%) have fallen in Tuesday trading after Amazon.com Inc. AMZN, -1.65% announced it was raising its minimum wage to $15 and advocating for a broader rise in the minimum wage to that level. Retailers, already feeling the pressure to attract and retain quality workers, could soon be feeling the tighter squeeze from larger, more competitive…