Here’s Wikipedia’s description of Nixon’s impeachment inquiry:

An impeachment process against Richard Nixon began in the United States House of Representatives on October 30, 1973, following the “Saturday Night Massacre” episode of the Watergate scandal. The House Judiciary Committee set up an impeachment inquiry staff and began investigations into possible impeachable offenses by Richard Nixon, the 37th President of the United States. The process was formally initiated on February 6, 1974, when the House of Representatives passed a resolution, H.Res. 803, giving the Judiciary Committee authority to investigate whether sufficient grounds existed to impeach Nixon[

Note the dates. The inquiry was started in the judiciary in October, 73, and the House didn’t approve the formal initiation until a little over four months later.