The following data is available from the question:

MS: M+ =  ?  g/mol. Lots of small peaks, not easy to see if an M+ is visible, but at least 68g/mol

IR:  There are no strong absorptions around 1715cm^-1 for a C=O band, 3300cm^-1 for O-H/N-H stretch, 1600cm^-1 for C=C, or 1100cm^-1 for C-O. There is an absorption at 2260cm^-1 for a either CºC or CºN.

13C nmr: The proton decoupled spectrum shows 4 peaks indicating 4 types of C.  By analysis of the chemical shifts, we have a deshielded C at 120 ppm and a peaks at 20ppm, 19ppm and 13ppm that are probably hydrocarbon portions.

1H nmr:  First of all we have 3 types of H showing up.  After this, it's a good idea to tabulate the information to make sure you get it all correctly matched up:
 

The coupling patterns for the -CH₃ (1.1ppm, triplet) and the -CH₂- (2.3ppm, triplet) indicate that they are both connected to  -CH₂- (1.7ppm, sextet) so we have an n-propyl group:  CH₃CH₂CH₂- .

Summary....

The only functional group indicated in the IR showed is a CºC or CºN.
13C peak at 120ppm suggests that this is a CºN (usually 110-125ppm) rather than CºC (usually 70-90ppm).
H nmr gave us an n-propyl chain =
So with this information we have the following pieces:  CH₃CH₂CH₂-  and -CºN.
Use this to check the molecular formula so far : C₄H₇N = 4 x 12 + 7 x 1 + 14 =  69 g/mol
This is at consistent with the minimum MW from the mass spectrum.

Altogether...

With the pieces we have :  CH3CH2CH2- and -CºN. This means we only have the 2 end groups which can only be out together in one way. Note the nitrile is supported by the IR CºN stretch and 13C chemical shift. H nmr gives the propyl chain. The nitrile group slightly deshields the attached methylene.

butyronitrile or n-propyl cyanide

The final step should always be to check what you have drawn.
The easiest thing to check is usually the coupling patterns you would expect to see, and the chemical shifts of each unit.
You should be asking yourself : "Does my answer give me what the H-nmr shows ?"