g | x | w | all

Bytes	Lang	Time	Link
008	Desmos	250528T200529Z	Aiden Ch
006	R	250528T143056Z	Martin M
011	Python 3	250528T135529Z	CrSb0001
006	JavaScript	250527T200746Z	doubleun
002	Don't know if my answer is valid. Here we go 2 distinct chars ! and \|.	250527T182654Z	sergiol
006	Google Sheets / Excel	250527T171908Z	z..
012	APL+WIN	250527T144052Z	Graham
013	PowerShell	250527T114537Z	user3141

Desmos, 8 distinct characters

Characters

a_(),=1-

False literal

Assigns a to 0

a=1-1

True literal

Assigns a_1 to 1

a_1=1

NAND function

Defines a_a as the NAND function

a_a(a,a_1)=1-aa_1

(Note: the function parameters a and a_1 are distinct from the variables defined as false and true earlier. Despite that, the program still works completely fine.)

Try It On Desmos!

Explanation:

a_(),=1-

a_: Need for naming (variables, functions, and function parameters)

(),: Needed for function definition

=: Assignment operator

1: Used as both the constant 1, and as a subscript for naming

-: Used to get 0 from 1, and in the NAND function definition

R, 6 distinct characters

F=\()&

F is the built-in false literal and reused in function/param names
= is an assignment operator (which is also used to define named functions). Also let's us build NOT as ==F
\ defines an anonymous function
() function call
& logical AND

the NAND definition is then:

FF=\(FF)\(FFF)((FF&FFF)==F)

We can the define the true literal as

FFF=FF(F)(F)

The full NAND truth table is then

FF(F)(F)
#TRUE
FF(F)(FFF)
#TRUE
FF(FFF)(F)
#TRUE
FF(FFF)(FFF)
#FALSE

If you want to define multiple functions or evaluate multiple expressions or define the function AND evaluate an expression you also need a single separator character (not counted above), either ; or newline will work.

Attempt it online

Python 3, 11 distinct characters

Characters used (note the space character \u20 and the start of the code block):

 *,-1:abdlm

Solution:

lambda a,aa:1-a*aa

Usage in the terminal (two examples):

>>> for i in [True, False]:
...     for j in [True, False]:
...         print( (lambda a,aa:1-a*aa)(i, j) )
...
0
1
1
1
>>> for i in [True, False]:
...     for j in [True, False]:
...         print( bool( (lambda a,aa:1-a*aa)(i, j) ) )
...
False
True
True
True

The reason this works is because in Python,

True  * True  == 1
True  * False == 0
False * True  == 0
False * False == 0

1 == int(True)
0 == int(False)

JavaScript, 6 distinct characters

In JavaScript, only []()!+ are required because JSF*ck.

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console.log(a(0,0));
console.log(a(0,1));
console.log(a(1,0));
console.log(a(1,1));

Don't know if my answer is valid. Here we go: 2 distinct chars ! and |.

Tcl, 27 bytes

proc N {a b} {expr !$a|!$b}

Try it online!

Google Sheets / Excel, 6 distinct characters

=1-A1*B1

Characters: {=, 1, -, A, *, B}

In GS/Excel AND(a,b) is logically equivalent to a*b and NOT(x) is logically equivalent to 1-x.

So NOT(AND(a,b)) is logically equivalent to NOT(a*b) which is logically equivalent to 1-a*b. (This is assuming a, b are either booleans, 1s or 0s)

APL+WIN, 12 distinct characters

NAND is a single character that takes a left and right argument which can be matching boolean arrays of any dimension. The following code prompts for a and b and outputs the NAND result. Try it online shows it for scalar, vector and 2d matrix inputs.

⎕⍲⎕

Try it online! Thanks to Dyalog Classic

PowerShell, 13 distinct characters

$o={!$args[!!$a]-or!$args[!$a]}

Try it online!

a nand b is the same as !(a and b), which is the same as !a or !b; implementing it using or avoids the need for round brackets before applying the ! operator after and (PS has no native -nand), and it also has less distinct characters than and.
$o = {...} defines an (unnamed) function and saves it in the variable $o (o because that character is already required for the operator -or).
Any positional parameters passed to the function will end up in the default array $args.
!!$a will evaluate to 0: $a starts out as $null, negating it will turn it to $true, negating it again will turn it $false, and using it as array index will turn it to 0.
Accordingly, !$a will evaluate to 1.