alternatehistory.com

African-American Presidents:
45. Ben Carson / Carly Fiorina (R, 2017-Present)
def. 2016: Cory Booker / Elizabeth Warren (D)
44: Barack Obama / Hillary Clinton (D, 2009-2017)
def. 2012: Herman Cain / Michele Bachmann (R)
def. 2008: Alan Keyes / Sarah Palin (R)
43: Colin Powell / Elizabeth Dole (R, 2001-2009)
def. 2004: Al Sharpton / Janet Napolitano (D)
def. 2000: Jesse Jackson / Jeanne Shaheen (D)
42: Douglas Wilder / Pat Schroeder (D, 1993-2001)
def. 1996: Colin Powell / Christine Todd Whitman (R), Alan Keyes / Ezola Foster (USTP)
def. 1992: Samuel Pierce / Nancy Kassebaum (R), Ron Daniels / Asiba Tupahache (I)
41: Samuel Pierce / Nancy Kassebaum (R, 1989-1993)
def. 1988: Jesse Jackson / Pat Schroeder (D)
40: William Coleman / Anne Armstrong (R, 1981-1989)
def. 1984: Jesse Jackson / Geraldine Ferraro (D)
def. 1980: Walter Washington / Barbara Jordan (D), Clifton DeBerry / Matilde Zimmerman (SW)
39: Walter Washington / Barbara Jordan (D, 1977-1981)
def. 1976: Edward Brooke / Carla Anderson Hills (R)
38: Edward Brooke / Margaret Chase Smith (R, 1974-1977)

That's about as far as I got. I imagine Fauntroy will be the McGovern proxy and Channing Phillips the Humphrey proxy, but I haven't figured out who would be a "good" Nixon.