Those are the chord diagrams for this approach:
G = 320003       C = X320010     D = XX0232     Dsus2 = XX0230
Strumming pattern goes:
G    G   C  C C   C  G    G   C  C C   C
Down,DownUP,UpDownUp-Down,DownUP,upDownup... 
Chords are super basic. One instrumental measure follows each verse, so play the G-C-G-C stuff after 
"take our time...", "know our mind...", "we won't care...", etc etc.
Listen to the record to get it right. 
Verse:
G           C     G          C          G    C   G   C         
   Let's be undecided, let's take our time
       D         C             D         G   C   G   C
   And sooner or later we will know our mind
G           C      G        C            G   C   G   C 
   We'll be on the outside, we won't care
      D             C      D               G C   G   C
   Because we're together, that's somewhere
Chorus:
              C       D      C        D         G   C   G   C
And there's a big day coming, 'bout a mile away
          C       D             C           G
There's a big day coming, I can hardly wait
G             C         G             C                G   C  G  C
   Let's wake up the neighbors, let's turn up our amps,
C      D           C           D            G  C  G  C
https://www.coveralia.com/acordes/big-day-coming--demo--yo-la-tengo.php
   The way that we used to, without a plan
G         C       G           C                  G  C  G  C
   We can play a Stones song, sitting on a fence,
              C             D  C        D                  G  C  G  C
   And it'll sound pretty good, till I forget how it ends
Chorus:
              C       D      C        D         G   C   G   C
And there's a big day coming, 'bout a mile away
          C       D             C           G
There's a big day coming, I can hardly wait
G    C       G               C                 G  C  G  C
   I woke up early, couldn't go back to sleep,
C         D           G        D                  G   C  G  C
   'Cause I'd been thinking of where it all would lead
G       C          G             C                  G  C  G  C
   So I made you wake up, said, "Let's take a walk,
           C           D C    D                   G  C  G  C
   I wanna hold your hand, we don't have to talk"
Chorus:
              C       D      C        D         G   C   G   C
And there's a big day coming, 'bout a mile away
          C       D             C           G
There's a big day coming, I can hardly wait
G        C           G C G C
   I can hardly wait
G        C           G C G C
   I can hardly wait.
(Ends in G)