Use the option -O and -osscan-guess also helps to discover OS information.

sudo -O 192.168.1.69

result:

Starting Nmap 6.40 ( http://nmap.org ) at 2016-07-08 00:24 BST
Nmap scan report for peter-laptop-1 (192.168.1.69)
Host is up (0.000037s latency).
Not shown: 997 closed ports
PORT    STATE SERVICE
80/tcp  open  http
139/tcp open  netbios-ssn
445/tcp open  microsoft-ds
No exact OS matches for host (If you know what OS is running on it, see http://nmap.org/submit/ ).
TCP/IP fingerprint:
OS:SCAN(V=6.40%E=4%D=7/8%OT=80%CT=1%CU=43939%PV=Y%DS=0%DC=L%G=Y%TM=577EE4B0
OS:%P=x86_64-pc-linux-gnu)SEQ(SP=106%GCD=1%ISR=107%TI=Z%CI=I%TS=8)SEQ(SP=10
OS:6%GCD=1%ISR=107%TI=Z%II=I%TS=8)OPS(O1=MFFD7ST11NW7%O2=MFFD7ST11NW7%O3=MF
OS:FD7NNT11NW7%O4=MFFD7ST11NW7%O5=MFFD7ST11NW7%O6=MFFD7ST11)WIN(W1=AAAA%W2=
OS:AAAA%W3=AAAA%W4=AAAA%W5=AAAA%W6=AAAA)ECN(R=Y%DF=Y%T=40%W=AAAA%O=MFFD7NNS
OS:NW7%CC=Y%Q=)T1(R=Y%DF=Y%T=40%S=O%A=S+%F=AS%RD=0%Q=)T2(R=N)T3(R=N)T4(R=Y%
OS:DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T5(R=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%
OS:O=%RD=0%Q=)T6(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T7(R=Y%DF=Y%T=40%
OS:W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)U1(R=Y%DF=N%T=40%IPL=164%UN=0%RIPL=G%RID=G%
OS:RIPCK=G%RUCK=G%RUD=G)IE(R=Y%DFI=N%T=40%CD=S)
 
Network Distance: 0 hops
 
OS detection performed. Please report any incorrect results at http://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 18.26 seconds